Cluster-Glass Phase in Pyrochlore XY Antiferromagnets with Quenched Disorder

Author(s)

Andrade, Eric C. ^[1] ; Hoyos, Jose A. ^[1] ; Rachel, Stephan ^{[2, 3]} ; Vojta, Matthias ^[2]

Affiliation

^[1] Univ Sao Paulo, Inst Fis Sao Carlos, CP 369, BR-13560970 Sao Carlos, SP - Brazil

^[2] Tech Univ Dresden, Inst Theoret Phys, D-01062 Dresden - Germany

^[3] Univ Melbourne, Sch Phys, Parkville, Vic 3010 - Australia

• Document type: Journal article
• Source: Physical Review Letters; v. 120, n. 9 MAR 2 2018.
• Web of Science Citations: 12

Abstract

We study the impact of quenched disorder (random exchange couplings or site dilution) on easy-plane pyrochlore antiferromagnets. In the clean system, order by disorder selects a magnetically ordered state from a classically degenerate manifold. In the presence of randomness, however, different orders can be chosen locally depending on details of the disorder configuration. Using a combination of analytical considerations and classical Monte Carlo simulations, we argue that any long-range-ordered magnetic state is destroyed beyond a critical level of randomness where the system breaks into magnetic domains due to random exchange anisotropies, becoming, therefore, a glass of spin clusters, in accordance with the available experimental data. These random anisotropies originate from off-diagonal exchange couplings in the microscopic Hamiltonian, establishing their relevance to other magnets with strong spin-orbit coupling. (AU)

• FAPESP's process: 16/10826-1 - Multi-user equipment approved in grant 2015/23849-7: computer cluster
• Grantee: Francisco Castilho Alcaraz
• Support Opportunities: Multi-user Equipment Program
• FAPESP's process: 15/23849-7 - Quantum spin chains
• Grantee: Francisco Castilho Alcaraz
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 13/00681-8 - Disordered magnets: ground state, excitations, and thermodynamics
• Grantee: Eric de Castro e Andrade
• Support Opportunities: Research Grants - Young Investigators Grants