Low-temperature transport properties of intermetallic compound HoAgGe with kagome spin ice state

Abstract

We study the magnetic susceptibility, magnetization, resistivity and thermal conductivity of intermetallic HoAgGe single crystals at low temperatures and in magnetic fields along the $a$ and $c$ axis, while the electric and heat currents are along the $c$ axis. The magnetization curves show a series of metamagnetic transitions and small hysteresis at low field for $B\parallel a$, and a weak metamagnetic transition for $B\parallel c$, respectively. Both the magnetic susceptibility and $\ddot{I}(T)$ curve show anomalies at the antiferromagnetic transition ($T{}_{\mathrm{N}}\sim$ 11.3 K) and spin reorientation transition ($\sim$ 7 K). In zero field and at very low temperatures, the electrons are found to be the main heat carriers. For $B\parallel a$, the $\ddot{I}(B)$ curves display large and positive transverse magnetoresistance (MR) with extraordinary field dependence between $B^2$ and $B$-linear, accompanied with anomalies at the metamagnetic transitions and low-field hysteresis; meanwhile, the $\hat{I}º(B)$ mainly decrease with increasing field and display some anomalies at the metamagnetic transitions. For $B\parallel c$, there is weak and negative longitudinal MR while the $\hat{I}º(B)$ show rather strong field dependence, indicating the role of phonon heat transport.

8 pages, 8 figures