# Interfacial Spin Seebeck effect in noncollinear magnetic systems

## TL;DR

This paper develops a comprehensive theoretical framework for understanding how heat-induced spin currents are generated at interfaces between noncollinear magnetic insulators and metals, extending previous models to more complex magnetic orders.

## Contribution

It introduces a general theory for thermally-driven spin transport at noncollinear magnetic interfaces, unifying and extending existing models for simpler magnetic systems.

## Key findings

- Derived a general expression for spin current in noncollinear magnets
- Reproduced known results for ferromagnetic and antiferromagnetic systems
- Provided a foundation for future experimental and theoretical studies

## Abstract

The interplay between spin and heat currents at magnetic insulator|nonmagnetic metal interfaces has been a subject of much scrutiny because of both fundamental physics and the promise for technological applications. While ferrimagnetic and, more recently, antiferromagnetic systems have been extensively investigated, a theory generalizing the heat-to-spin interconversion in noncollinear magnets is still lacking. Here, we establish a general framework for thermally-driven spin transport at the interface between a noncollinear magnet and a normal metal. Modeling the interfacial coupling between localized and itinerant magnetic moments via an exchange Hamiltonian, we derive an expression for the spin current, driven by a temperature difference, for an arbitrary noncollinear magnetic order. Our theory reproduces previously obtained results for ferromagnetic and antiferromagnet systems.