Evidence of variable range hopping in Zintl phase EuIn2P2

We report a comprehensive characterization of the magnetic, electrical transport, Raman spectra, and thermal properties of the single-crystalline Zintl-type material ${\mathrm{EuIn}}_{2}{\mathrm{P}}_{2}$. The compound crystallizes with a hexagonal unit cell (space group $P{6}_{3}/mmc$) and orders magnetically at ${T}_{\mathrm{C}}=24$ K with the Eu magnetic moments aligned ferromagnetically within the $ab$ plane but tilted alternately along the $c$-axis direction. The effective and saturation magnetic moments agree with the theoretical values expected for the ${\mathrm{Eu}}^{2+}$ ion. For a range of several tens of kelvins above $\ensuremath{\sim}40$ K, the electrical transport of ${\mathrm{EuIn}}_{2}{\mathrm{P}}_{2}$ is dominated by short-range magnetic interactions. The temperature dependence of the electrical resistivity was modeled in terms of variable-range hopping. Another indication of the latter scenario seems to be the observation, for ${\mathrm{EuIn}}_{2}{\mathrm{P}}_{2}$, of a quadratic dependence of the negative magnetoresistance on the magnetic field strength and the scaled magnetization. The temperature dependence of the Raman band position and FWHM, as well as the phonon lifetime, confirms the presence of the distinctive regions observed in transport and magnetic studies.