Thermal expansion of α-manganese from 2–300°K

Thermal expansion and thermodynamic characterization of antiferromagnetic phase transition in elementalα-Mn

“…For example, in agreement with our results, both diffraction studies [15,30] and the data in Ref. [22] suggest that the thermal expansion of α-Mn is negative for T < T N . White has previously compared the negative thermal expansion of α-Mn with similar behavior in Invar and other magnetically ordered metals [28], speculating that it is due to the volume dependence of the magnetic exchange interactions.…”

“…This latter issue makes it difficult to calculate Ω ≡ d(ΔV/V )/dT with much confidence. Finally, the most complete study published [22] for α-Mn used an optical technique to measure thermal expansion between 2 and 300 K with a resolution that is about one order of magnitude lower than that of our measurements [29]. Nevertheless, our measurements of ΔV/V for α-Mn, displayed in Fig.…”

“…Observations of critical behavior in α-Mn were previously reported in experiments measuring nuclear relaxation time [21], adiabatic compressibility [19], reduced hyperfine fields [20], thermal expansion [22], and the temperaturedependent intensities of magnetic Bragg reflections from neutron diffraction [14]. However, only a few studies have attempted to extract critical exponents.…”

“…A measurement of the thermal expansion of α-Mn by an optical technique was reported in Ref. [22] with resolution of 8 × 10 −7 , but this is about an order of magnitude lower than the relative resolution of 10 −8 that can be achieved in capacitance dilatometry systems [29]. The temperature dependence of lattice parameters, obtained from X-ray [30] and neutron [15] diffraction studies, has also been reported, but the coefficient of thermal expansion cannot be confidently obtained from such sparse data.…”

On the third-generation Calphad databases: An updated description of Mn

“…A Néel temperature for α‐Mn equal to 100 K was first reported by neutron diffraction studies of Shull and Wilkinson and later approved by heat capacity measurement . However, other measurements of heat capacity , thermal expansion , electric resistance , magnetic susceptibility , and elastic moduli revealed a Néel temperature equal to 95 (±2) K which was adopted in the present assessment.…”