## 3 Results and Discussion
### NLR-M2 Results
Figure 3: Dependences on static field \(H\) of phase components of \(M_{2}\) response, ReM\({}_{2}\)(\(H\)) (open blue and solid red circles) and ImM\({}_{2}\)(\(H\)) (open green and solid black stars), for MSR-1 strain recorded at frequencies of \(H\)-scan \(F_{\rm sc}\)= 8 and 0.25 Hz are presented in panels (**a,b,d,e**). Solid symbols present the curves recorded at direct \(H\)-scan and open symbols are used for curves registered at the reverse sweep. For clarity, this is additionally indicated by arrows having the same color as the color of the corresponding symbols. Panels (**c,f**) display ReM\({}_{2}\)(\(H\)) dependences registered at \(F_{\rm sc}\)= 0.02 Hz and their best fits (black lines). Red and green lines correspond to two components of entire signal (see text). The upper panels (**a,b,c**) reflect the magnetic state of “fresh” (”new”) bacteria and lower panels (**d,e,f**) characterize the state of bacteria after one year of storage (“old”). The hatched peaks in (**f**) present \(M_{2}\) response simulated for the NPs 40 nm size. Figure 5: Dependences on static field H of phase components of M2 response, ReM2(H) (open blue and solid red circles) and ImM2(H) (open green and solid black stars), for AMB-1 strain recorded at frequencies of H-scan Fsc= 8 and 0.25 Hz are presented in panels (**a**,**b**,**d**,**e**). Solid symbols present the curves recorded at direct H-scan and open symbols are used for curves registered at the reverse sweep. For clarity, this is additionally indicated by arrows having the same color as the color of the corresponding symbols. Panels (**c**,**f**) display ReM2(H) dependences registered at Fsc= 0.02 Hz and their best fits (black lines). Red and green lines correspond to two components of entire signal (see text). The upper panels (**a**–**c**) reflect the magnetic state of “fresh” (“new”) bacteria and lower panels (**d**–**f**) characterize the state of bacteria after one year of storage (“old”). The hatched peaks in (**f**) present M2 response simulated for the NPs 40 nm size. Figure 6: Dependences on static field H of phase components of M2 response, ReM2(H) (open blue and solid red circles) and ImM2(H) (open green and solid black stars), for SP-1 strain recorded at frequencies of H-scan Fsc= 8 and 0.25 Hz are presented in panels (**a**,**b**,**d**,**e**). Solid symbols present the curves recorded at direct H-scan and open symbols are used for curves registered at the reverse sweep. For clarity, this is additionally indicated by arrows having the same color as the color of the corresponding symbols. Panels (**c**,**f**) display ReM2(H) dependences registered at Fsc= 0.02 Hz and their best fits (black lines). Red and green lines correspond to two components of entire signal (see text). The upper panels (**a**–**c**) reflect the magnetic state of “fresh” (“new”) bacteria and lower panels (**d**–**f**) characterize the state of bacteria after one year of storage (“old”). As shown in Figures 3-6, the 8 Hz \(M_{2}\) response exhibits a large field hysteresis. Decreasing the hysteresis with the scan frequency suggests its dynamical nature and the stable single-domain state of the magnetosomes. The vanishing of the hysteresis at \(F_{\rm sc}\) = 0.02 Hz indicates proximity of the magnetosome ensemble to the SPM regime, opening the possibility of using the FP formalism. The imaginary component of the response coming from high-frequency magnetization dynamics [34; 35; 36] is significantly smaller than the real component. Our fitting of the \(M_{2}\) response, taking into account the imaginary component, yielded the Gilbert damping factor of the order 10. Therefore, only the real part of the response was processed further, without taking into account the Im\(M_{2}\) component. The signals registered at \(F_{\rm sc}\) = 8 Hz exhibited two peaks, indicating two fractions in the distribution of magnetic moments. Two peaks, somewhat less pronounced, were also present in the responses recorded at \(F_{\rm sc}\) = 0.25 Hz.