CPP- Giant Magnetoresistance and Thermo-Electric Power of multilayers

TL;DR

This paper investigates oscillations in magnetoresistance and thermo-electric power in multilayer structures using a tight-binding model, revealing complex oscillation behaviors and phase differences.

Contribution

It introduces a theoretical analysis of oscillations in GMR and TEP in multilayers, highlighting non-RKKY type long-period oscillations and phase differences.

Findings

Oscillations can have one or two periods.

Long period oscillations are of non-RKKY type.

TEP oscillations are strongly enhanced and phase-shifted.

Abstract

Oscillations of magnetoresistance and thermo-electric power (TEP) vs. both nonmagnetic spacer as well as ferromagnetic slab thicknesses are studied in the current-perpendicular-to-plane (CPP) geometry, in terms of a single-band tight-binding model. The spin-dependent conductance has been calculated from the Kubo formula by means of a recursion Green's function technique, and the $ TEP $ directly from the well-known Onsager relations. In general, the observed oscillations may have either just one or two periods. In the latter case the long period of oscillations, related to spectacular beats, is apparently of non-RKKY type. The relative TEP oscillations are strongly enhanced in comparison with those of the giant magnetoresistance, have the same periods, but different phases and a negative bias.