Synthesis and magnetic characterization of TmCo2B2C

TL;DR

This study reports the synthesis, structural analysis, and magnetic characterization of a new TmCo2B2C intermetallic compound, revealing its magnetic properties and absence of superconductivity down to very low temperatures.

Contribution

It introduces a new TmCo2B2C compound, details its crystal structure, magnetic behavior, and compares its properties with related compounds, highlighting the effects of rapid-quench synthesis.

Findings

TmCo2B2C has a stable isomorphous structure with TmNi2B2C.

Paramagnetic behavior follows modified Curie-Weiss law above 7 K.

Long-range ferromagnetic order appears around 1 K, no superconductivity detected down to 20 mK.

Abstract

A new quaternary intermetallic borocarbide TmCo2B2C has been synthesized via a rapid-quench of an arc-melted ingot. Elemental and powder-diffraction analyses established its correct stoichiometry and single-phase character. The crystal structure is isomorphous to that of TmNi2B2C(I4/mmm) and is stable over the studied temperature range. Above 7 K, the paramagnetic state follows the modified Curie-Weiss behavior (X=C/(T-theta)+X0 wherein X0=0.008(1) emu/mole and the temperature-dependent term reflecting the paramagnetism of the Tm subsystem: ueff=7.6(2) uB [in agreement with the expected value for a free Tm3+ ion] and theta = -4.5(3) K. Long range ferromagnetic order of the Tm sublattice is observed to develop around ~1 K. No superconductivity is detected in TmCo2B2C down to 20 mK, a feature which is consistent with the general trend in the RCo2B2C series. Finally, the influence of the rapid-quench process on the magnetism (and superconductivity) of TmNi2B2C will be discussed and compared to that of TmCo2B2C.