Science. 1964 Aug 7;145(3632):575-7. doi: 10.1126/science.145.3632.575.
The electrical resistance of dysprosium was studied in the temperature-pressure range 77 degrees to 200 degrees K and 15 to 120 kb. The variations of the Néel transition with pressure was found to good accuracy, the value of dT(N)/dP being-0.62+/-0.4 deg/kb. From this result, second-order thermodynamic equations yield values of -64 x 10-6 ( degrees C)(-1) and 4.0 x 10(-14) cm(2)/dyne for the changes in the coefficient of linear expansion and the compressibility, respectively, at the 1-atm Néel point. The Néel transition disappears at 45 to 55 kb, and no magnetic transitions are seen at higher pressures in the temperature range indicated. The other boundaries in the region investigated have been determined but are very uncertain. The cause of the cusp in the isothermal compressions is not clear from the available data. Above the Néel boundary, the pressure dependence of the cusp with respect to temperature, dP/dT, is very small and may even be zero. Below the Néel temperature, dP/dT is uncertain. From isothermal measurements, the value is -1, while from the isobaric measurements a value of -0.25 is obtained.
研究了钽在 77 度至 200 度 K 和 15 至 120 kb 的温度-压力范围内的电阻。发现奈尔转变随压力的变化非常准确，dT（N）/dP 值为-0.62+/-0.4 度/kb。根据这个结果，二阶热力学方程得出了在 1 大气压奈尔点处线性膨胀系数和压缩率的变化值分别为-64 x 10-6（摄氏度）（-1）和 4.0 x 10（-14）cm（2）/dyne。奈尔转变在 45 至 55 kb 时消失，在所研究的温度范围内，在更高的压力下没有观察到磁转变。已确定该区域的其他边界，但非常不确定。从现有数据来看，尚不清楚等温压缩中拐点的原因。在奈尔边界以上，拐点随温度的压力依赖性 dP/dT 非常小，甚至可能为零。在低于奈尔温度的情况下，dP/dT 不确定。从等温测量中得到的值为-1，而从等压测量中得到的值为-0.25。
