Talk:Magnetocrystalline anisotropy

Nickel
Room-temperature anisotropy constants ( × 104 J/m3 ).[1]

Structure 	K1 	K2

Ni 	−0.5 	−0.2

This doesn't seems right. K2 should be positive for metallic nickel. — Preceding unsigned comment added by 85.254.89.70 (talk) 11:26, 13 April 2018
 * Why do you think it should be positive? In Table 1 of, various sources give values of K2 between -2.3 and -5.1, so actually -0.2 may not be negative enough. RockMagnetist(talk) 17:24, 13 April 2018 (UTC)

There seems to be some discrepancy concerning the sign of K2 for nickel:

1. "Determination of the magnetic anisotropy constant K2 of cubic ferromagnetic substances" (1957) by Sato and Chandrasekhar https://www.sciencedirect.com/science/article/abs/pii/0022369757900112

2. "Temperature Dependence of the Magnetocrystalline Anisotropy Constants K1 and K2 of Nickel" (1965) by Tatsumoto et al. https://journals.jps.jp/doi/abs/10.1143/JPSJ.20.1541

3. Wohlfarth's book (Table 12, based on publications from Escudier and Franse de Vries) https://www.sciencedirect.com/science/article/pii/S1574930405801166 — Preceding unsigned comment added by 85.254.89.70 (talk) 08:40, 16 April 2018 (UTC)
 * I notice the dates of those publications are all relatively early. In Darby and Isaac, on page 295, they say that the early results were highly inconsistent, but newer results were agreeing on a negative value for K2. Maybe I'll add a note to that effect. RockMagnetist(talk) 15:58, 16 April 2018 (UTC)
 * I hope you'll contribute to some Wikipedia articles. You clearly have the research skills! RockMagnetist(talk) 15:59, 16 April 2018 (UTC)