Temperature dependence of surface magnetization in local-moment systems

Abstract

We present a theory to study the temperature-dependent behavior of surface states in a ferromagnetic semi-infinite crystal. Our approach is based on the single-site approximation for the s-f model. The effect of the semi-infinite nature of the crystal is taken into account by a localized perturbation method. Using the mean-field theory for the layer-dependent magnetization, the local density of states and the electron-spin polarization are investigated at different temperatures for ordinary and surface transition cases. The results show that the surface magnetic properties may differ strongly from those in the bulk and the coupling constant of atoms plays a decisive role in the degree of spin polarization. In particular, for the case in which the exchange coupling constant on the surface and between atoms in the first and second layer is higher than the corresponding in the bulk, an enhancement of surface Curie temperature and hence the spin polarization can be obtained.

Tunnel magnetoresistance of a CnBN (n = 58 and 68) molecular junction

“…The origin of this difference is the asymmetry of the surface density of states (SDOS) of the FM electrodes for spin-up and spin-down electrons [39], and the quantum tunneling phenomenon through the molecule. The only assumption we have to make is that spin is conserved during tunneling; the current can be described as two partial currents, one for the spinup electrons and the other for the spin-down electrons.…”

Surface‐Sensitive Detection of Magnetic Phase Transition in Van Der Waals Magnet CrSBr

“…Moreover, the magnetic order at the topmost surface layer in Pd was found to be strongly different from the bulk, yielding a high surface T C far above the bulk. [ 29,30 ] In the 2D vdW magnet CrSiTe 3 [ 31,32 ] and CrGeTe 3 , [ 33 ] the magnetic correlations within the ab ‐plane were also reported to persist to temperatures far above the bulk T C . A recent work demonstrated significant 2D intralayer magnetic correlations in the ab ‐plane of CrSBr above T N by neutron scattering.…”