Relaxation dynamics of magnetization transitions in synthetic antiferromagnet with perpendicular anisotropy

Abstract

Two synthetic antiferromagnet bilayer systems with strong perpendicular anisotropy CoFeB/Ta/CoFeB and Pt/Co/Ir/Co/Pt have been grown using sputtering techniques. For both systems two types of magnetization transitions have been studied. The first one concerns transitions from a state where magnetizations of the two magnetic layers are parallel (P state) to a state where magnetizations of the two layers are aligned antiparallel (AP state). The second one concerns transitions between the two possible antiparallel alignments (AP+ to AP-). For both systems and both transitions after-effect measurements can be understood in the frame of nucleation-propagation model. Time derivative analysis of magnetic relaxation curves and mapping of the first order reversal curves at different temperature allowed us to demonstrate the presence of different pinning centers, which number can be controlled by magnetic field and temperature.

Effect of Fe/Fe3O4 Nanoparticles Stray Field on the Microwave Magnetoresistance of a CoFeB/Ta/CoFeB Synthetic Ferrimagnet

“…All of these experimentally determined energies were reported in our previous publications. 31,43 The dP″/dH(H) dependence (Figure 3b) demonstrated four different areas separated by the same three critical fields in Figure 3a. The field dependence of dP″/ dH allowed one to detect changes in the magnetization of the layers by nonresonant microwave absorption.…”

Условия возникновения спонтанной осциллирующей магнитной релаксации в синтетических ферримагнетиках Pt/Co/Ir/Co/Pt

“…Толщины слоев определялись исходя из времени их напыления. Аттестация магнитных свойств образца приведена в [4]. Перпендикулярная магнитная анизотропия (ПМА) обусловлена гибридизацией 3d орбитального момента Со с 5d орбитальным моментом Pt и Ir [5].…”

Magnetic Relaxation in Two Dimensional Assembly of Dipolar Interacting Nanoparticles

“…In these applications, the dynamics of nanoparticles is primarily characterized by Néel relaxation time, which depends on various vital parameters such as particle size, anisotropy constant, temperature and magnetic interaction, etc. [15][16][17][18]. Therefore, the study of magnetic relaxation in such a system represents a topic of great interest.…”