Anomalous remnant magnetization in dilute antiferromagnetic Gd1−xYxB4

Abstract

Magnetic properties of dilute single crystals of ${\mathrm{Gd}}_{1\ensuremath{-}x}{\mathrm{Y}}_{x}{\mathrm{B}}_{4}$ ($x=0$, 0.2, and 0.4) were systematically studied. These antiferromagnetic Shastry-Sutherland compounds display a remnant magnetization $M{}_{\mathrm{R}}$ when field cooled below the N\'eel temperature ${T}_{\mathrm{N}}$. The magnitude of $M{}_{\mathrm{R}}$ at low magnetic fields is magnetic field dependent, increasing with increasing magnetic fields, and it saturates for $H\ensuremath{\le}30$ Oe. The ${M}_{R}(T)$ data for both $x\phantom{\rule{0.16em}{0ex}}=\phantom{\rule{0.16em}{0ex}}0.2$ and 0.4 compositions overlap, and the remnant magnetization follows a universal behavior. We argue that these findings are explained by taking into account the formation of magnetic domains within the crystals, originating from the dilution of a magnetically frustrated, antiferromagnetic sublattice.