Low temperature heat capacity of Nd2Zr2O7 pyrochlore

Abstract

Heat capacity of neodymium zirconate (Nd 2 Zr 2 O 7) with pyrochlore structure was measured by adiabatic calorimetry and the hybrid adiabatic relaxation method in the temperature range (0.45 to 400) K. Its excess component was obtained by comparison with the heat capacity of the lanthanum zirconate. A thermal anomaly was observed below T ¼ 7:2 K. From the heat capacity measurements, the thermodynamic functions of Nd 2 Zr 2 O 7 were determined.

Standard Gibbs Energy of Formation of Mg<SUB>3</SUB>La Determined by Solution Calorimetry and Heat Capacity Measurement from Near Absolute Zero Kelvin

“…The C p values of Mg 0:75 La 0:25 were measured in the temperature range of 2-400 K by using a relaxation method [14][15][16][17] instrument (PPMS, Quantum Design, San Diego, USA). The C p (Mg 0:75 La 0:25 ) values above 400 K were measured by DSC (Model DSC-404, Netzsch, Bayern, Germany).…”

“…The standard enthalpies of formation, Á f H o , were determined by using a new Calvet-type calorimeter equipped with a new thermoelectric device 13) and the standard entropies of formation, Á f S o , were determined by measuring C p from near absolute zero (2 K) to 400 K by the recently developed method of relaxation calorimetry [14][15][16][17] and C p over 400 K by the differential scanning calorimeter (DSC). 9,17) In this paper, we focused attention on the Mg-La system, which was a part of the Mg-Zn-RE (RE ¼ La) system.…”

Heat Capacity of La<SUB>1&minus;<I>X</I></SUB>Sr<I><SUB>X</SUB></I>FeO<SUB>3&minus;&delta;</SUB> from 2 K to 1340 K

“…In our previous study, the C p values of an oxide 11) and intermetallic compounds [12][13][14] were determined by the recent developed method of a relaxation calorimetry [15][16][17] at 2-400 K and a heat flow stabilized differential scanning calorimetry (DSC) 11,14) at 400-1340 K. The errors by the relaxation method and DSC were found to be less than 1% 11,12) and 3%, 14) respectively, indicating that highly reliable data are obtainable. Thus, in the present study, accurate C p values at 2-1340 K for La 1ÀX Sr X FeO 3À were measured by combining the relaxation method with the DSC method.…”

Determination of Standard Gibbs Energy of Formation of Al<SUB>2</SUB>Nd by Solution Calorimetry and Heat Capacity Measurement from Near Absolute Zero Kelvin

“…Recently relaxation method [10][11][12][13] has been developed to measure heat capacity, C p , at very low temperature. Since a small amount (5{30 mg) of a sample is enough to measure C p , this method [10][11][12][13] can change the sample temperature rapidly.…”

“…Since a small amount (5{30 mg) of a sample is enough to measure C p , this method [10][11][12][13] can change the sample temperature rapidly. In our previous studies, [13][14][15][16][17][18] the standard entropies of formation at 298 K, Á f S o 298 , of intermetallic compunds [14][15][16][17][18] and an oxide 13) were determined by measuring C p from near absolute zero Kelvin (2 K) by the relaxation method.…”