High-Pressure Magnetic Properties and P–T Phase Diagram of Iron Borate

摘要: The high-pressure magnetic states of iron borate 57FeBO3 single-crystal and powder samples have been investigated in diamond anvil cells by nuclear forward scattering (NFS) synchrotron radiation at different temperatures. In the low-pressure (0 < P 46 GPa) antiferromagnetic phase, an increase Neel temperature from 350 to 595 K induced pressure was found. At pressures 46–49 GPa, a transition new state with weak moment (magnetic collapse) discovered. It is attributed electronic Fe3+ ions high-spin 3d 5 (S = 5/2, 6 A 1g ) low-spin 1/2, 2 T 2g ) (spin crossover) due insulator-semiconductor-type extensive suppression strong d-d electron correlations. low temperatures, NFS spectra phase indicate correlations system ordering about 50 K. A tentative P-T diagram FeBO3 proposed. An important feature this presence two triple points where paramagnetic phases coexist.