Successive phase transitions in the hexagonal-layered Heisenberg antiferromagnets MnX2 (X = Br, I)

✍ Scribed by T. Sato; H. Kadowaki; K. Iio

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 191 KB
• Volume: 213-214
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/0921-4526(95)00112-m

✦ Synopsis

Successive magnetic phase transitions in the Heisenberg antiferromagnets MnX2 (X = Br, I) have been studied by neutron diffraction. Two (TN~ = 2.32 K and TN2 = 2.17 K) and three (TNt = 3.95 K, TN2 = 3.8 K and TN3 = 3.45 K) transitions were observed in the bromide and the iodide, respectively. In both compounds, transverse sinusoidally modulated structures occur in the intermediate phases (MnBr2:TN2 < T < TN~; MnI2:TN3 < T < TN~), whereas the T~,L~, (MnBr2) and helical (MnI2) structures occur through first-order transitions in the lowest-temperature phases. The successive transitions are brought about by several competing exchange interactions and the dipole interaction.