Phase separation and interface properties in an artificial frustrated ice magnet

• Grant number: 23/00132-6
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate (Direct)
• Start date: September 11, 2023
• End date: September 10, 2024
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Kleber Roberto Pirota
• Grantee: Breno Malvezzi Cecchi
• Supervisor: Nicolas Rougemaille
• Host Institution: Instituto de Física Gleb Wataghin (IFGW). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Institution abroad: Institut NÉEL, France
• Associated to the scholarship: 19/23317-6 - Spin waves in artificial spin ice formed by ferro- and antiferromagnets: a new magnonic crystal representative, BP.DD

Abstract

Artificial spin ices are lithographically patterned arrays of nanomagnets that have become well-established experimental platforms to investigate cooperative and exotic phenomena in frustrated spin lattice models. Ising-like nanomagnets arranged on a kagome lattice, known as artificial kagome spin ice (AKSI), provides a particularly rich phase diagram with four magnetic phases: a high-temperature paramagnet; two distinct spin liquids, the so-called spin ice 1 (SI1) and spin ice 2 (SI2) phases; and a long-range ordered (LRO) ground state. Recent works have been able to reproducibly achieve all of the non-trivial SI1, SI2 and LRO phases, giving access to the intriguing at-equilibrium physics of AKSI. In this project, we would like to go a step further and investigate what happens when those phases are put in contact. In particular, the goal of the project is to understand to what extent a spin liquid can "crystallize" when in contact with a magnetically ordered state, or reciprocally to what extent a magnetically ordered phase can "melt" when in contact with a spin liquid. Addressing these questions requires to characterize the properties of such a liquid/solid magnetic interface, and to understand its role in the crystallization/melting process. Similar questions will be addressed by putting in contact two distinct spin liquids (SI1 and SI2). In that case, we will investigate the question of their miscibility. The experimental approach will be based on the fabrication of AKSI structures presenting a phase coexistence, following a recipe developed recently in the host lab. As shown below, although the project is innovative and challenging, preliminary results have been obtained, demonstrating the feasibility of the project proposal within a one year time constraint. (AU)