The Geometrically Frustrated Spin Glass (Fe1-pGap)2TiO5

TL;DR

This study investigates the magnetic properties of Fe2TiO5 and its Ga-doped variants, revealing strong geometric frustration and specific heat behavior indicative of a spin glass state influenced by magnetic cluster interactions.

Contribution

It provides new experimental data on susceptibility, specific heat, and neutron scattering for Fe2TiO5 with Ga doping, highlighting the role of geometric frustration in its spin glass behavior.

Findings

Susceptibility at T_g increases as T_g decreases with doping

Specific heat follows a T^2 dependence at low temperatures

Doping suppresses T_g and enhances magnetic frustration

Abstract

The unusual anisotropy of the spin glass transition in the pseudobrookite system Fe$_2$TiO$_5$ has been interpreted as arising from an induced, van der Waals-like, interaction among magnetic clusters. Here we present susceptibility ($\chi$) and specific heat data (C) for Fe2TiO5 diluted with non-magnetic Ga, (Fe$_{1-p}$Ga$_p$)$_2$TiO$_5$, for disorder parameter p = 0, 0.11, and 0.42, and elastic neutron scattering data for p = 0.20. A uniform suppression of T{_g} is observed upon increasing p, along with a value of $\chi (T_g)$ that increases as T$_g$ decreases, i.e. $d\chi(T_g)/dT_g< 0$. We also observe C(T) $\propto$ T$^2$ in the low temperature limit. The observed behavior places (Fe$_{1-p}$Ga$_p$)$_2$TiO$_5$ in the category of a strongly geometrically frustrated spin glass.