Magnetic Phases and Specific Heat of Ultra-Thin Holmium Films

TL;DR

This paper models the magnetic phases and specific heat of ultra-thin Holmium films, revealing how size, surface effects, and magnetic fields influence phase behavior and transition characteristics.

Contribution

It provides new insights into the magnetic phase diagram of ultra-thin Ho films, highlighting the effects of slab size, surface, and magnetic fields on phase transitions.

Findings

Reduced external field needed for saturation in thin films

Helical state does not form in ultra-thin films

Heat capacity and susceptibility elucidate phase transition nature

Abstract

We report model calculations of the magnetic phases of very thin Ho films in the temperature interval between 20K and 132K, and show that slab size, surface effects and magnetic field due to spin ordering may impact significantly the magnetic phase diagram. There is a relevant reduction of the external field strength required to saturate the magnetization and for ultra-thin films the helical state does not form. We explore the heat capacity and the susceptibility as auxiliary tools to discuss the nature of the phase transitions.