Effect of pressure on magneto-transport properties in the superconducting andnormal phases of the metallic double chain compound Pr2 Ba4 Cu7 O15−δ
Masayoshi Kuwabara,1 Michiaki Matsukawa,1, ∗ Keisuke Sugawara,1 Haruka Taniguchi,1 Akiyuki
Matsushita,2 Makoto Hagiwara,3 Kazuhiro Sano,4 Yoshiaki Ono,5 and Takahiko Sasaki6

arXiv:1609.00125v1 [cond-mat.supr-con] 1 Sep 2016

1

Department of Materials Science and Engineering, Iwate University, Morioka 020-8551, Japan
2
National Institute for Materials Science, Ibaraki 305-0047
3
Kyoto Institute of Technology, Kyoto 606-8585,Japan
4
Department of Physics Engineering, Mie University, Tsu 514-8507,Japan
5
Department of Physics, Niigata University, Niigata 950-2181,Japan
6
Institute for Materials Research, Tohoku University, Sendai 980-8577,Japan(Dated: September 2, 2016)

To examine the electronic phase diagram of superconducting CuO double chains, we report
the effect of external pressure on the magneto-transport properties in superconducting and nonsuperconducting polycrystalline samples of Pr2 Ba4 Cu7 O15−δ at low temperatures (1.8-40 K) undervarious magnetic fields (up to 14 T). In the as-sintered non-superconducting sample, the magnetoresistance (MR) follows a power law of H 3/2 at low temperatures, which is in no agreement with
the H 2 dependence of MR in the PrBa2 Cu4 O8 system. The negative pressure dependence of thesuperconducting phase is qualitatively consistent with a theoretical prediction on the basis of theTomonaga-Luttinger Liquid theory. The 48-h-reduced superconducting sample at ambient pressure
exhibits no clear increase in MR for T > Tc,on = 26.5 K. In contrast, with the application of pressure
to the superconducting sample, the MR effects reappear and are also well fitted by H 3/2 . The modelof slightly warped Fermi surfaces explains not only the MR effect of the non-superconducting sample,
but is also related to the reasons for the pressure-induced MR phenomena of the superconducting
sample.
PACS numbers: 74.25.Ha,74.25.F-,74.90.+nI.

INTRODUCTION

Since the discovery of high-Tc copper-oxide superconductors, researches have focused on the unconventional
superconductivity on the two-dimensional CuO2 planes
in some cuprates. In quasi one-dimensional (1D) ladder system without CuO2 planes, it is well known thatthe superconductivity at Tc = 12 K appears only under
the application of high pressure.1 In our previous studyof Pr-based cuprates with metallic CuO double chains
and insulating CuO2 planes, Pr2 Ba4 Cu7 O15−δ is foundto be a new superconductor with a higher Tc (15 K) after a reduction treatment.2 A nuclear quadrupole resonance (NQR) study has revealed that the newly discovered superconductivity is realized at the CuO doublechain block.3
Structurally, the Pr-based cuprates, PrBa2 Cu3 O7−δ(Pr123) and PrBa2 Cu4 O8 (Pr124), are identical totheir corresponding Y-based high-Tc superconductors,
YBa2 Cu3 O7−δ (Y123) and YBa2 Cu4 O8 (Y124). Pr123
and Pr124 compounds have insulating CuO2 planes andare non-superconductive.4,5 The suppression of superconductivity in the Pr substitutes has been explained by thehybridization of Pr-4f and O-2p orbitals.6 The crystal
structure of Pr124 with CuO double chains differs fromthat of Pr123 with CuO single chains. It is well known
that CuO single chains in Pr123 and CuO double chainsin Pr124 show semiconducting and metallic behaviors,
respectively.7 The carrier concentration of doped double
chains of Pr124 is difficult to vary, because it is thermallystable up to high temperatures.
The compound Pr2 Ba4 Cu7 O15−δ (Pr247) is an intermediate between Pr123 and Pr124. In this compound,CuO single-chain and double-chain blocks are alternately
stacked along the c-axis such as {-D-S-D-S-} sequence8,9(see Fig.1). Here, S and D denote CuO single-chain anddouble-chain blocks along the b-axis, respectively. The
physical properties of the metallic CuO double chains canbe examined by controlling the oxygen content along thesemiconducting CuO single chains. Anisotropic resistivity measurements of single-crystal Pr124 have revealed
that metallic transport arises by the conduction along
the CuO double chains.10 In oxygen removed polycrystalline Pr2 Ba4 Cu7 O15−δ , the superconductivity appears
at an onset temperature Tc,on of ∼15 K.2 Hall coefficientmeasurements of superconducting Pr247 with Tc,on = 15
K have revealed that at intermediate temperatures below 120 K, the main carriers change from holes to electrons, as the temperature decreases. Accordingly, thiscompound is an electron-doped superconductor.11 In ourprevious study, we examined the effect of magnetic fields
on the superconducting phase of Pr247.12 Despite of theresistive drop associated with the superconducting transition, we found that the diamagnetic signal was strongly
suppressed as expected in the 1D superconductivity of
CuO double chains. We also reported the temperaturedependence of the Hall coefficient in superconducting
Pr247 with a higher Tc,on ∼ 27 K.13 Our findings indicated that the superconducting transition temperature
increased because the density of doped electron carriers

2became denser under the reduction treatment, consistent
with a theoretical prediction.14
In this paper, we demonstrate the magneto-transport
properties of the electron-doped metallic double-chain
compound Pr2 Ba4 Cu7 O15−δ , which has a higher Tc,on(26.5 K), under the application of different hydrostatic pressures (up to 1.6 GPa). Section II outlines
the experimental methods, and Sec. III presents themagneto-transport properties of superconducting andnon-superconducting polycrystalline Pr247 samples under external pressures. These results are discussed in
the view point of topologies of Fermi surfaces, which arevaried from warped to straight form upon increasing thecarrier content. The final section is devoted to a summary.

S

EXPERIMENT

Polycrystalline samples of Pr2 Ba4 Cu7 O15−δ (Pr247)
were synthesized by the citrate pyrolysis method.15 After several annealing processes, the resulting precursors
were pressed into a pellet and calcined at 875-887 ◦ C
for an extended period over 120-180 h under ambient
oxygen pressure. The oxygen in the as-sintered sample
was removed by reduction treatment in a vacuum at 500◦
C for 48 h, yielding a superconducting material. Typical dimensions of the pelletized rectangular sample were
9.9 × 2.4 × 1.7 mm3 . X-ray diffraction data revealed thatthe as-sintered polycrystalline samples are an almost single phase with an orthorhombic structure (Ammm), as
shown in Fig.1. The lattice parameters of the as-sinteredsample are a = 3.8753 Å, b = 3.9107 Å, and c = 50.713
Å, which are in fair agreement with those obtained by aprevious study16 . In a previous TEM image of superconducting Pr247, we observed a regular stacking structureof {-D-S-D-S-} along the c-axis direction17 . The oxygen
deficiency in the sample with Tc,on = 26.5 K prepared by
the citrate method was estimated to be δ = 0.56 fromgravimetric analysis. As a function of the oxygen deficiency, the Tc,on rises rapidly at δ ≥∼ 0.2, then monotonically increases with increasing δ, and finally saturates
around 26-27 K at δ ≥∼ 0.6.18 Accordingly, the carriersin the present sample are concentrated around the optimally doped region.
The electric resistivity in zero magnetic field was measured by the dc four-terminal method. The magnetotransport up to 9 T was measured by the ac fourprobe method using a physical property measuring system (PPMS, Quantum Design), increasing the zero-fieldcooling (ZFC) temperatures from 2 K to 40 K. The highfield resistivity (up to 14 T) was measured in a superconducting magnet at the High Field Laboratory for
Superconducting Materials, Institute for Materials Research, Tohoku University. The electric current I wasapplied longitudinally to the sample ; consequently, theapplied magnetic field H was transverse to the sample(because H ⊥ I). Hydrostatic pressures in the electric

Intensity (arb. unit)II.

resistivity measurement were applied using a clamp-type
CuBe/NiCrAl cell up to 1.6 GPa. Fluorinert was used asa pressure transmitting medium. Inner and outer cylinders were made of NiCrAl and CuBe alloys, respectively.
The dc magnetization was performed under ZFC in
a commercial superconducting quantum interference device magnetometer (Quantum Design, MPMS). The
magnetization measurement under applied pressure wasconducted using a standard clamp-type pressure device.
A simple clamp cell consists of a ZrO2 piston and cylinder
made of a CuBe alloy. The M/H values of the clamp-type
cell are estimated to be ∼ 10−8 emu/g and are considerably smaller than the values of M/H for all samples.

c
b
a

D

(004)

10

20

30
40
2q (deg.)50

60Fig. 1: (color online) X-ray diffraction patterns of as-sinteredpolycrystalline Pr2 Ba4 Cu7 O15−δ . The (004) peak corresponds to one of typical Miller indexes of Pr247. The calculated curve is obtained using the lattice parameters in the
text. Inset shows the crystal structure of Pr247. S and D
denote CuO single-chain and double-chain blocks along theb-axis, respectively.

III.

RESULTS AND DISCUSSION

Figure 2 shows the temperature dependences of electric resistivities of the as-sintered non-superconducting
and 48-h-reduced superconducting samples measured under various pressures ((a)0.GPa and 0.8 GPa, (b) 0 GPa,
0.4 GPa, 0.8 GPa, 1.2 GPa, and 1.6 GPa). For comparison, inset of Fig.2 plots low-temperature dependencesof magnetic susceptibilities χ of the superconducting
sample under various pressures (up to 1.2 GPa). Firstof all, the superconductivity of the 48-h-reduced sample was suppressed with increasing the applied pressure.
When applied pressures exceed 0.8 GPa, zero-resistancestate of the 48-h-reduced sample then disappeared. Second, the high-temperature metallic properties of the reduced superconducting sample were changed to the semiconducting behaviors at applied pressures above 0.8 GPa,
accompanied by a rapid increase in ρ. The onset temperature of superconducting transition Tc,on is suppressed

3
15

30

(a) as-sintered(a) as-sintered 0 GPa

0.8 GPa
0 GPa

25

10

0
-0.0010GPa
0.8GPa1.2GPa-0.002-0.0035-0.004

0

50

9T
0T
5

0 GPa
0.8 GPa∆ρ /ρ (0) (%)

ZFC 5mT

100

ρ (mΩ cm)15
χ (emu/gOe)ρ (mΩ cm)

2010

µ 0 H =9 (T)

5

0

5

100

10

15 20
T (K)

150

25

200

10

30

250

0

300

0

5

10

15

T (K)

30

25

30

40

35

40

T (K)

8

15

20

20
T (K)

(b) as-sintered(b) 48-h-reduced

0 GPa (30K)10∆ρ /ρ(0) (%)ρ (m Ω cm)

6

1.6 GPa
1.2 GPa
0.8 GPa
0.4 GPa
0 GPa

5

0.8 GPa (30K)
0 GPa (40K)
0.8 GPa (40K)

4

2

0

0
0

50

100

150
T (K)

200

250

300

0

2

4

6

µ0H (T)

8

10

Fig. 2: (color online) (a) Temperature dependences ofelectric resistivities of the as-sintered non-superconducting
Pr2 Ba4 Cu7 O15−δ compound measured under 0 GPa and 0.8
GPa. (b) Temperature dependences of electric resistivitiesof the 48-h-reduced superconducting Pr2 Ba4 Cu7 O15−δ compound measured under various pressures (0 GPa, 0.4 GPa, 0.8
GPa, 1.2 GPa and 1.6 GPa). Inset plots low-temperature dependences of magnetic susceptibilities χ of the 48-h-reduced
superconducting sample measured under several pressures (upto 1.2 GPa).

Fig. 3: (color online) (a) Low-temperature dependences ofelectric resistivities of the as-sintered non-superconducting
Pr2 Ba4 Cu7 O15−δ compound measured under a zero field andan applied field of 9 T. Inset plots the magneto-resistancedata of the as-sintered sample ∆ρ/ρ(0) versus T (below 40K) under 0 GPa and 0.8 GPa. Here, ∆ρ = ρ(H) − ρ(0).
In (b), the magneto-resistance data of the as-sintered sample∆ρ/ρ(0) are plotted as a function of H (up to 9 T) at T = 30
K and 40 K under both P = 0 GPa and 0.8 GPa.
.

from 26.5 K under ambient pressure through 24.1 K under 0.8 GPa to 18.0 K under a maximum pressure of 1.6
GPa. (Tc,on versus pressure at a zero field as displayed
in inset of Fig.7) The normal-superconducting phase diagram of CuO double chains has been investigated on
the basis of the Tomonaga-Luttinger Liquid theory.14
When the distance between the two single chains of a
CuO double-chain@block shrinks along the c-axis, thehopping energies tpp and tdd are expected to increase.
Here, tpp and tdd represent the hoping term between 2pσ
orbitals at the nearest neighbor oxygen sites and thatbetween 3dx2 −y2 orbitals at the nearest neighbor copper
sites, respectively. The application of the external pressure on the CuO double chains causes an enhancement of
the hopping terms, resulting in a phase transition fromthe superconducting to normal phase. This theoreticalprediction is qualitatively consistent with the supercon-

ducting properties suppressed by the pressure effect.19
As shown in Fig. 2, the pressure effect on the electronic transports of the as-sintered non-superconducting
sample is quite weak , in both its magnitude and temperature dependence, in comparison with that of the 48h-reduced superconducting sample. (These behaviors of
the present as-sintered Pr247 are almost similar to theeffect of pressure on the temperature dependence of assintered Pr247 compound prepared by high-pressure synthesis technique.20 )Next, let us show in Fig. 3 the temperature dependences of electric resistivities of the as-sintered nonsuperconducting Pr2 Ba4 Cu7 O15−δ compound measured
under a zero field and an applied field of 9 T. Inset of
Fig. 3 plots the magneto-resistance (MR) data of theas-sintered sample ∆ρ/ρ(0) versus T (between 4 K and40 K) under 0 GPa and 0.8 GPa. The value of ∆ρ/ρ(0)taken at 9 T reaches a maximum of about 12 % near

412(a) 0 GPa∆ρ /ρ(0) (%)

10

2K
5K
10K
15K
20K
30 K
40 K

8
6
4

9T

2
0

0

25

10

15

20

(µ0H) 3/2 (T

3/2

25

30

)

(b) 0.8GPa20∆ρ /ρ(0) (%)

5

6K
30K

15

40K

10
14T
5
9T
0

0

10

20

30

40

(µ0H)

3/2

3/2

(T

50

60

)

Fig. 4: (color online) Magneto-resistance effect ∆ρ/ρ(0) of
the as-sintered non-superconducting Pr2 Ba4 Cu7 O15−δ compound. In (a), the MR data (up to 9 T) under ambientpressure are plotted as a function of H 3/2 at the selected
temperatures (T =2 K-40 K). In (b), the MR data (up to 14T) under 0.8 GPa are plotted as a function of H 3/2 at the
selected temperatures of T = 5 K, 30 K, and 40 K.
.

10 K under either 0 GPa or 0.8 GPa. Moreover, themagneto-resistance curves as a function of applied field
follow similar field dependences in the both cases of 0
GPa and 0.8 GPa. Accordingly, we infer that application of pressure on the as-sintered sample gives rise to no
considerable variation in the magneto-resistance effect.
Here, we try to fit the field dependence of the MR
effect ∆ρ/ρ(0) by using a power law of H. As shownin Fig.4, we found out that ∆ρ/ρ(0) of the as-sintered
Pr247 sample at ambient pressure is well scaled with
H 3/2 over a wide range of temperatures (2 K-40 K). Ina similar way, the MR data of the as-sintered sample
recorded at 0.8 GPa are well described by a power lawof ∆ρ/ρ(0) ∝ H 3/2 . Our findings are not consistent with
the MR effect of polycrystalline Pr124 compounds withmetallic double-chains. In Pr124 system, ∆ρ/ρ(0) ∝ H 2
for H ⊥ I.22 These discrepancies in magnetic field dependences of MR between Pr124 and Pr247 are originated from the differences of their crystal structures.

In the latter compounds, we believe that CuO double
chains stacked along the c-axis are separated by CuO
singe chains, resulting in a suppression of carrier hopping between individual double chains along the c-axis.
Furthermore, a photoemission spectroscopy study23 hasrevealed that the CuO double chain in Pr247 has a betterone dimensionality than that in Pr124, which is probably
close to the suppression of c-axis carrier hopping.
In Pr124 system, it is well known that the interchain transport at low temperatures is destroyed by ahigh magnetic field applied perpendicular to the CuO
double chains.24 The field-induced dimensional-crossovercauses the weak field dependence of the c-axis magnetoresistance of Pr124 when the applied field exceeds thedecoupling field of 11 T. Furthermore, in Y124 system,
the field dependence of the c-axis magneto-resistance ischanged from H 2 to H-linear dependence at high fields,suggesting the field-induced dimensional crossover.25 An
anomalous field dependence of the c-axis MR ( ∆ρ ∝H 3/2 ) has been reported in the 1D organic conductor(TMTSF)2 PF6 once the inter-chain transport becomesincoherent.26 For Pr124 or Y124 with {-D-D-D-D-} sequence, the c-axis hopping of carriers between CuO double chains is suppressed by the application of highly magnetic field. In Pr247 system, the c-axis carrier transport
is originally incoherent because of regular stacking structures of {-D-S-D-S-} along the c-axis direction, as depicted in Fig.1.
Figure 5 (a) plots the low-temperature dependences of electric resistivities of the superconducting
Pr2 Ba4 Cu7 O15−δ compound with Tc,on = 26.5 K in several applied fields (0 T, 3 T, 6 T, 10 T, and 14 T). Even athigh fields above 10 T, the resistive drop associated withthe superconducting transition is observed but the diamagnetic signal is strongly suppressed at low field below
1 T. This observation is closely related to the 1D superconductivity of CuO double-chains as highlighted in
our previous paper.12 The magneto-resistance effect (upto 14 T) of the 48-h-reduced superconducting sample in
the normal sate temperature region above Tc,on = 26.5
K is very small in comparison to the large MR effectof the as-sintered sample. ∆ρ/ρ of the as-sintered sample recorded at 30 K attains ∼ 7% up to 9 T while forthe 48-h-reduced sample the MR effect rapidly decreases
below ∼ 1% at 9 T. The suppressed MR effect in thenormal phase of the 48-h-reduced superconducting sample is probably explained by the topology of Fermi surfaces of CuO double chains27 , where the Fermi surfaces
are changed from their warped to straight forms uponincreasing carrier contents. (as mentioned below)
Figure 6 plots the low-temperature dependencesof electric resistivities of the superconducting
Pr2 Ba4 Cu7 O15−δ compound measured in the several applied fields (0 T-14 T) under various hydrostaticpressures ((a)P = 0.4 GPa, (b)P = 1.2 GPa, and (c)P
=1.6 GPa). For the superconducting sample withoutmagnetic field, the superconducting transition temperature reaching zero-resistance state Tc,zero is suppressed5
2.5

ρ (mΩ cm)

1.5

14 T
10 T
6T
3T
0T

1

0.5

5

10

15

20

25

30

35

ρ (m Ω cm)

3
Tc, on =26.5K

00ρ (mΩ cm)

14T
12T
6T
3T
0T

0
40

(b) 48-h-reduced
1.2 GPa8

ρ (m Ω cm)

2

1

2
1.5

0.5

2.5 (b) 48-h-reduced 0 GPa

30K
20K
4K

Tc, on =25.3K

2.5

1

T (K)

1.5

(a) 48-h-reduced
0.4 GPa

3.5(a) 48-h-reduced
0 GPa
2

7

Tc, on =20.1K

6
14T
10T
6T
3T
0T

5
4

3K
1.7K

3

(c) 48-h-reduced
1.6 GPa

0.5
0

0

2

4

6

8

µ0H (T)

10

12

14

Fig. 5: (color online) (a) Low-temperature dependencesof electric resistivities of the 48-h-reduced superconducting
Pr2 Ba4 Cu7 O15−δ compound measured at the several appliedfields (H = 0 T-14 T). In (b), the magneto-resistance data of
the superconducting sample are plotted as a function of magnetic fields (up to 14 T) at the selected temperatures (T =1.7 K-30 K).
.

from 16 K at 0 GPa down to 6 K at a low pressure of
0.4 GPa. At high fields above 10 T, the low-temperature
data under 0.4 GPa remain the resistive drops associatedwith the superconducting transition, upon decreasing
temperature. These tendencies still appear for thehigh-field resistive data (up to 10 T) under both 1.2
GPa and 1.6 GPa.
For temperatures close to Tc,on , we are concentrated
on the magneto-transport properties in the normal stateof the 48-h-reduced superconducting sample. As mentioned before, although the strong MR effect is observedin the as-sintered non-superconducting sample, the 48-hreduced annealing procedure for it causes a considerably
suppression of the normal-state MR accompanied by theappearance of the superconductivity with Tc,on = 26.5
K. The application of pressure on the superconducting
sample gives rise to a substantial decrease of Tc,on from26.5 K at 0 GPa down to Tc,on = 18 K at 1.6 GPa, as
shown in inset of Fig. 7. On the other hand, the finiteρ (m Ω cm)

9
8

T

c, on

=18.0K
14T
10T
6T
3T
0T

7
6
5

0

5

10

15

20
25
T (K)

30

35

40

Fig. 6: (color online) Low-temperature dependences ofelectric resistivities of the 48-h-reduced superconducting
Pr2 Ba4 Cu7 O15−δ compound measured at several appliedfields under hydrostatic pressures of (a)0.4 GPa, (b) 1.2 GPa,and (c) 1.6 GPa. For H = 0 Tesla, Tc,on is decreased from25.3 K at 0.4 GPa through 20.1 K under 1.2 GPa to 18.0 K
under a maximum pressure of 1.6 GPa.
.

magneto-resistance effect reappears for T ≥ Tc,on when
the applied pressure to the superconducting sample isincreased.
Figure 7 plots the magneto-resistances (up to 14 T)of the 48-h-reduced superconducting sample, ∆ρ/ρ(0),measured under a maximum pressure of 1.6 GPa. For
T > Tc,on = 18 K, ∆ρ/ρ(0) curves initially start to increase in the the downward convey forms with appliedfields. On the other hand, the MR data recorded at T
below Tc,on = 18 K tend to increase according to the
upward covey behaviors at low fields.
In a similar way to the MR of the as-sintered sample,

6

15

15

(a) 1.6 GPa

20K
25K
30K
40K

10

∆ρ /ρ(0) (%)∆ρ /ρ(0) (%)(a) 1.6 GPa

5

0

0

5

10

µ0H (T)

10

14T

5

0

15

9T

20K
25K
30K
35K
40K

0

10

20

25

(b) 1.6 GPa

10

4.3 K

8

∆ρ /ρ(0) (%)

15K

15

1/3*∆ρ/ρ(0)

c, on

(K)

10

Normal30
20T∆ρ /ρ(0) (%)

40

(µ0H)

3/2

3/2

(T

50

60

)

(b) 30K

20

SC

10

5

0

0

30

0

5

µ0H (T)

0

0.4

10

0.4GPa

14T
9T

1.2GPa6

1.6GPa42

0.8 1.2 1.6
P (GPa)0
15

Fig. 7: (color online) Magneto-resistances (up to 14 T) of the
48-h-reduced superconducting sample for temperatures close
to Tc,on = 18 K under a maximum pressure of 1.6 GPa . For
T > Tc,on and T < Tc,on , the MR data are presented in (a)and (b), respectively. Inset plots Tc,on versus pressure (up to
1.6 GPa).
.

the MR data of the superconducting sample recorded
under 1.6 GPa are well described by a power law of∆ρ/ρ(0) ∝ H 3/2 over the normal state region between
20 K and 40 K, as shown in Fig.8 (a). For comparison,
Fig.8 (b) shows the MR data at T = 30 K under P =0.4 GPa, 1.2 GPa, and 1.6 GPa. The application of pressures on the superconducting sample enhances the MR
at 14 T from 2.2 % at 0.4 GPa through 5.8 % at 1.2 GPa
up to 8 % at 1.6 GPa. Furthermore, the MR data underpressures are well fitted by using ∆ρ/ρ(0) ∝ H 3/2 .(Fig.
8(b))
Now, we try to discuss the pressure-induced magnetoresistance effect of the 48-h-reduced superconducting
sample. First of all, we assume that the Fermi surfacesof the double chains of the superconducting Pr247 are almost straight as indicated by the band calculation.28 In
an ideal 1D conductor with straight Fermi surface without the wave number ky , the orbitals of itinerant carries across the CuO double chains are not bended by the
Lorentz force, resulting in no MR effect. In the case of

0

10

20

30
40
(µ0H) 3/2 (T 3/2 )50

60

Fig. 8: (color online)The corresponding MR data (up to 14T) are plotted as a function of H 3/2 . The data of (a) and (b)are collected under P = 1.6 GPa at T = 20 K, 25 K, 30 K,
35 K, and 40 K, and at T = 30 K under P = 0.4 GPa, 1.2
GPa, and 1.6 GPa, respectively.
.

warped Fermi surface, the itinerant carriers have the finite component of wave number across the CuO double
chain direction and the Lorentz force can bend their orbitals, giving the classical MR effect. For the superconducting Pr247, CuO double chains have straight Fermi
surfaces at ambient pressure, which is consistent withthe absence of MR effect observed. On the other hand,
if the Fermi surfaces of double chains under the externalpressures are changed to their warped structures with finite values of ky . then it is naturally understood that theMR effects appear with increasing the applied pressure.
In particular, the lattice shrinkage due to the hydrostaticpressure enhances not only charge transfer across two single chains of a CuO double chain but also increase thecouplings between CuO double chains along the a-axis.
As mentioned before, the suppressed MR effect of the superconducting sample under ambient pressure is closely
related to the topology of Fermi surfaces of CuO double
chains, which are varied from their warped to straightforms upon increasing carrier contents. Accordingly, we
expect that the model of warped Fermi surfaces is not7only applicable to the origins of the MR effect of thenon-superconducting sample, but is also related to thereasons for the pressure-induced MR phenomena of thesuperconducting sample.
IV.

SUMMARY

We demonstrated the magneto-transport properties of superconducting and non-superconducting
Pr2 Ba4 Cu7 O15−δ compounds under the application ofdifferent hydrostatic pressures (up to 1.6 GPa). We
found out that ∆ρ/ρ(0) of the as-sintered Pr247 sample
at ambient pressure is well scaled by using H 3/2 overa wide range of temperatures (2 K-40 K). In present
Pr247 system, crystal structures of {-D-S-D-S-} along
the c-axis direction probably make inter-chain couplings
between CuO double chains incoherent, resulting in the
H 3/2 dependence of MR. This result of Pr247 is notconsistent with the H 2 dependence of MR in Pr124
system with stacking structures of {-D-D-D-D-} along
the c-axis. The superconducting properties suppressedby the pressure effect is qualitatively explained by thenormal-superconducting phase diagram of CuO double
chains on the basis of the Tomonaga-Luttinger Liquid
theory. The 48-h-reduced annealing procedure for theas-sintered sample causes a considerably decrease in theElectronic address: matsukawa@iwate-u.ac.jp
M. Uehara, T. Nagata, J. Akimitsu, H. Takahashi, N. Mori,
and K. Kinoshita, J. Phys. Soc. Jpn., 65 (1996) 2764.
2
M. Matsukawa, Y. Yamada, M. Chiba, H. Ogasawara, T.
Shibata, A. Matsushita, and Y. Takano, Physica C 411(2004) 101.
3
S. Watanabe, Y. Yamada and S. Sasaki, Physica C 426-431(2005) 473.
4
L. Soderholm, K. Zhang, D. G. Hinks, M. A. Beno, J.
D. Jorgensen,C. U. Segre, and I. K. Schuller, Nature 328(1987) 604.
5
S. Horii, Y. Yamada, H. Ikuta, N. Yamada, Y. Kodama,
S. Katano,Y. Funahashi, S. Morii, A. Matsushita, T. Matsumoto, I. Hirabayashi, and U. Mizutani,Physica C 302(1998) 10.
6
R. Fehrenbacher and T. M. Rice, Phys. Rev. Lett. 70(1993) 3471.
7
T. Mizokawa, C. Kim, Z. -X. Shen, A. Ino, T. Yoshida, A.
Fujimori, M. Goto, H. Eisaki, S. Uchida, M. Tagami, K.
Yoshida, A. I. Rykov, Y. Siohara, K. Tomimoto, S. Tajima,Yuh Yamada, S. Horii, N. Yamada, Yasuji Yamada, and I.
Hirabayashi, Phys. Rev. Lett. 85 (2000) 4779.
8
P. Bordet, C. Chaillout, J. Chenavas, J. L. Hodeau, M.
Marezio,J. Karpinski, and E. Kaldis, Nature 334 (1988)
596.
9
Y. Yamada, S. Horii, N. Yamada, Z. Guo, Y. Kodama,
K. Kawamoto,U. Mizutani, and I. Hirabayashi, Physica C
231(1994)131.
10
S. Horii, U. Mizutani, H. Ikuta, Y. Yamada, J. H. Ye, A.
Matsushita, N. E. Hussey, H. Takagi, and I. Hirabayashi,∗
1

normal-state MR accompanied by the appearance of thesuperconductivity with Tc,on = 26.5 K. The suppressedMR effect of the superconducting sample is probably
explained by the topology of Fermi surfaces of CuO double chains, where the Fermi surfaces are changed fromtheir warped to straight forms upon increasing carrier
contents. In contrast, for T > Tc,on , the applicationof pressure (up to 1.6 GPa) on the superconducting
sample results in a substantial MR effect of 8% at 14 T.
In a similar way to the MR of the as-sintered sample,
the MR data of the superconducting sample recorded
under 1.6 GPa are well described by a power law of∆ρ/ρ(0) ∝ H 3/2 over the normal state region between
20 K and 40 K. The model of slightly warped Fermi
surfaces explains not only the magneto-resistance effectof the non-superconducting sample, but it also is closely
related to the reasons for the pressure-induced MR
phenomena of the superconducting sample.

Acknowledgments

The authors are grateful for M. Nakamura for his assistance in PPMS experiments at Center for Regional
Collaboration in Research and Education, Iwate University.

Phys. Rev. B61 (2000) 6327.
A. Matsushita, K. Fukuda, Y. Yamada, F. Ishikawa, S.
Sekiya,M. Hedo, and T. Naka, Science and Technology ofAdvanced Materials 8 (2007) 477.
12
T. Chiba, M. Matsukawa, J. Tada, S. Kobayashi, M. Hagiwara, T. Miyazaki, K. Sano, Y. Ono, T. Sasaki, andJ.Echigoya, J. Phys. Soc. Jpn., 82 (2013) 074706.
13
J. Tada, M. Matsukawa, T. Konno, S. Kobayashi, M. Hagiwara, T. Miyazaki, K. Sano, Y. Ono, and A. Matsushita,
J. Phys. Soc. Jpn., 82 (2013) 105003.
14
K. Sano, Y. Ono, and Y. Yamada, J. Phys. Soc. Jpn., 74(2005) 2885.
15
M. Hagiwara, T. Shima, T. Sugano, K. Koyama, and M.
Matsuura, Physica C 445-448 (2006) 111.
16
Y. Yamada and A. Matsushita, Physica C 426-431 (2005)
213.
17
T. Konno, M. Matsukawa, K. Sugawara, H. Taniguchi, J.
Echigoya, A. Matsushita, M. Hagiwara, K. Sano, Y. Ono,
Y. Yamada, T. Sasaki, and Y. Hayasaka, Physica C 521522 (2016) 13.
18
M. Hagiwara, S. Tanaka, T. Shima, K. Gotoh, S. Kanda,
T. Saito, and K. Koyama, Physica C 468 (2008) 1217.
19
F. Ishikawa, K. Fukuda, S. Sekiya, A. Kaeriyama, Y. Yamada and A. Matsushita, J. Phys. Soc. Jpn., 76 (2007)
Suppl. A 92.
20
A. Matsushita, Y. Yamada, N. Yamada, S. Horii, and T.
Matsumoto, Physica C 242 (1995) 381.
21
N. Wakeham, and N. E. Hussey, Phys. Rev. B85 (2012)
235117.
22
I. Terasaki, N. Seiji, S. Adachi, and H. Yamauchi, Phys.
11

8
Rev. B54 (1996) 11993.
Y. Wakisaka, K. Takubo, T. Sudayama, J. Y.Son, T. Mizokawa, M. Arita, H. Namatame, M. Taniguchi, S. Sekiya,
K. Fukuda, F. Ishikawa, and Y. Yamada, J. Phys. Soc.
Jpn., 77 (2008) 074710.
24
N. E. Hussey, M. N. McBrien, L. Balicas, J. S. Brooks, S.
Horii, and H. Ikuta, Phys. Rev. Lett. 89 (2002) 086601.
25
N. E. Hussey, M. Kibune, H. Nakagawa, N. Miura, Y. Iye,
H. Takagi, and S. Adachi, and K. Tanabe, Phys. Rev. Lett.
23

80 (1998) 2909.
G. M. Danner, and P. M. Chaikin, Phys. Rev. Lett. 75(1995) 4690.
27
T. Nakano, K. Kuroki, and S. Onari, Phys. Rev. B76 (2007)
014515.
28
T. Habaguchi, Y. Ono, H. Y. Du Gh, K. Sano, and Y.
Yamada, J. Phys. Soc. Jpn., 80 (2011) 024708.
26