Anomalous magnetic properties of the paramagnetic phase and spin polarons in manganese monosilicide

作者：Demishev S V^*; Ishchenko T V; Samarin A N

来源：Low Temperature Physics, 2015, 41(12): 971-978.

DOI：10.1063/1.4938743

We consider the field dependence of magnetization in the paramagnetic phase of manganese monosilicde, MnSi, which is characterized by an anomalously large effective magnetic moment mu* = 5.3 mu(B), and a small saturation magnetization M-0 = 0.3 mu(B)/Mn. It follows from the conducted analysis, that neither the theory of band magnetism, nor the cluster approach can explain the experimental data, but an adequate description is possible within the framework of the spin-polaron model, in which the spin-polaron is a quasi-bonded state of the band electron and localized magnetic moment of Mn. It is found that the inclusion of specific interaction for a simple ferrimagnet-like configuration that characterizes the spin-polaron, allows us to explain the experimental data, wherein the observed values of mu* are not associated with large localized magnetic moments in the sample volume. The possible methods of experimental verification of the spin-polaron model are analyzed, including experimentum crucis. The obtained results show that the paramagnetic phase of MnSi should be regarded as a phase in which its physical properties are determined by the magnetic inhomogeneities on a nanometer spatial scale.

• 出版日期2015-12