| Summary: | The YbCoC<sub>2</sub> compound, which crystallizes in a base-centered orthorhombic unit cell in the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>A</mi><mi>m</mi><mi>m</mi><mn>2</mn></mrow></semantics></math></inline-formula> space group CeNiC<sub>2</sub> structure, is unique among Yb-based compounds due to the highest magnetic ordering temperature of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>T</mi><mi>N</mi></msub><mo>=</mo><mn>27</mn></mrow></semantics></math></inline-formula> K. Magnetization measurements have made it possible to plot the <i>H</i>-<i>T</i> magnetic phase diagram and determine the magnetocaloric effect of this recently discovered high-temperature heavy-fermion compound, YbCoC<sub>2</sub>. YbCoC<sub>2</sub> undergoes spin transformation to the spin-polarized state through a metamagnetic transition in an external magnetic field. The transition is found to be of the first order. The dependencies of magnetic entropy change <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>Δ</mo><msub><mi>S</mi><mi>m</mi></msub><mrow><mo>(</mo><mi>T</mi><mo>)</mo></mrow></mrow></semantics></math></inline-formula>—have segments with positive and negative magnetocaloric effects for <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>Δ</mo><mi>H</mi><mo>≤</mo><mn>6</mn></mrow></semantics></math></inline-formula> T. For <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>Δ</mo><mi>H</mi><mo>=</mo><mn>9</mn></mrow></semantics></math></inline-formula> T, the magnetocaloric effect becomes positive, with a maximum <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>Δ</mo><msub><mi>S</mi><mi>m</mi></msub><mrow><mo>(</mo><mi>T</mi><mo>)</mo></mrow></mrow></semantics></math></inline-formula> value of 4.1 J (kg K)<sup>−1</sup> at <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>T</mi><mi>N</mi></msub></semantics></math></inline-formula> and a refrigerant capacity value of 56.6 J kg<sup>−1</sup>.
|
|---|