Magnetoelastic coupling and phases in the skyrmion lattice magnet<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>Gd</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>PdSi</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:mrow></mml:math>discovered by high-resolution dilatometry
S. Spachmann, A. Elghandour, Matthias Frontzek, W. Löser, R. Klingeler
Abstract
We report detailed thermodynamic studies on high-quality single crystals of the centrosymmetric skyrmion-hosting intermetallic ${\mathrm{Gd}}_{2}{\mathrm{PdSi}}_{3}$ by means of high-resolution capacitance dilatometry in fields up to 15 T which are complemented by specific heat and magnetization studies. Our dilatometric measurements show magnetoelastic effects associated with antiferromagnetic order at ${T}_{\mathrm{N}1}=22.3$ K and ${T}_{\mathrm{N}2}=19.7$ K, as well as strong field effects in an applied magnetic field of 15 T up to 200 K (150 K) for $B\ensuremath{\parallel}c$ ($B\ensuremath{\parallel}a$*, i.e., $B\ensuremath{\perp}c$). The data allow us to complete the magnetic phase diagram, including a feature at ${T}^{*}\ensuremath{\approx}13\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ below which an additional degree of freedom becomes relevant. The magnetic B vs T phase diagram for the $a$* axis is also reported. Gr\"uneisen analysis shows the onset of magnetic contributions around 60 K, i.e., well above ${T}_{\mathrm{N}1}$. Uniaxial pressure dependencies of opposite signs, $\ensuremath{-}1.3$ and 0.3 K/GPa, are extracted for the out-of-plane and in-plane directions at ${T}_{\mathrm{N}1}$. For ${T}^{*}$ we obtain $\ensuremath{\partial}{T}^{*}/\ensuremath{\partial}{p}_{c}=1.4$ K/GPa. In particular we elucidate thermodynamic properties of the recently discovered skyrmion lattice phase and show that it is strongly enhanced by uniaxial pressure.