Electronic Structure of Ferromagnetic Perovskite Manganite Thin Films
Investigated by Hard X-ray Photoemission Spectroscopy
Hidekazu Tanaka1, Takeshi Yanagida1, Masatoshi Ohnishi1, Tomoji Kawai1, YasutakaTakata2, Koji Horiba 2, Munetaka Taguchi2, Shik Shin2, Daigo Miwa 2, Kenji Tamasaku2,
Yoshinori Nishino2, Tetsuya Ishikawa2, Eiji Ikenaga3, Masaaki Kobata3, Jung-Jin Kim3,Shigenori Ueda3, Mitsuhiro Awaji 3, Akihisa Takeuchi3, Keisuke Kobayashi31ISIR-Sanken, Osaka Univ., 8-1 Mihogaoka, Ibaraki, Osaka, 567-0047, JapanRIKEN/SPring-8, 1-1-1, Mikazuki-cho, Sayo-gun, Hyogo 679-5148, Japan3
JASRI/SPring-8, 1-1-1 Kouto, Mikazuki-cho, Sayo-gun, Hyogo 679-5198, Japan2

Photoemission intensity (arb. unit)

arb. unit)
Photoelectron Intensity ((arb.

Transition metal oxides exhibits a rich variety of electric and magnetic properties including colossal
magnetoresistance, ferromagnetism with metallic conduction, perfect spin polarization, charge/orbital ordering
due to the strong coupling between spin, and charge, and are also important in relation to applications
pertaining to spintronic heterostructure devices working at room temperature. We report the bulk sensitive Hard
X-ray core level photoemission spectroscopy to investigate the intrinsic electronic structure of perovskite
manganites, typically the strained (La,Ba)MnO3 thin films [1] showing enhanced ferromagnetism and electrondoped (Nd,Ce)MnO3 thin film [2].
In case of the strained (La,Ba)MnO3 thin films, a new sharp satellite peak appeared at the low energy siteof the Mn 2p3/2 main peak in a 20nm thick well-strained film withat 20Khv =5.95keV
strongly enhanced ferromagnetism, whereas a broader signal was(1)
observed for the unstrained film with 300nm thickness as shown in Fig.1.
20nm
Cluster calculations revealed that the intensity corresponded to the(TC=299K)
density of the state at the Fermi level relating to the magnitude of theferromagnetic order. The satellite intensity also agreed quantitatively with300nm
the square of the magnetization.
(TC=282K)(2)
In case of (Nd, Ce)MnO3 thin film, it can be seen that there is a648644640636
clear difference between NCeMO and LBMO thin films on the spectra,
Binding Energy (eV)indicating the existence of Mn2+, i.e. the mixed valence state of Mn2+ andFig. 1: Mn 2p core level spectra
Mn3+ within NCeMO film as shown in Fig.2. It should be noted that theseof (La0.85Ba0.15)MnO3 thin films
experimental results, especially the stoichiometry of NCeMO film on themicrostructure and the mixed valence state of Mn2+ and Mn3+, areMn3+
LBMO thin film
Mn4+demonstrated for the first time.
NCeMO thin film
Mn2+
For ferromagnetic manganite, Hard X-ray core level
Mn:2p3/2
photoemission spectroscopy makes it possible to estimate the electronic
hv=7941eV
structure directly related to the magnetization at deep depths even
without any surface treatment, and we believe that it can play animportant role in the development of novel functional magnetic, electrical
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and optical devices constructed using transition metal oxides.
Binding energy (eV)[1] H. Tanaka et al, Phys. Rev. B, 73 (2006) 094403[2] T. Yanagida et al, Phys.. Rev. B, 73 (2006) 132503

Fig. 2: Mn 2p core-level spectra ofNCeMO film and of LBMO film.