title: Temperature-dependent Raman and IR studies of multiferroic MnWO4 doped with Ni2+ ions.
abstract: Temperature-dependent Raman and IR studies of MnWO(4) crystal doped with Ni(2+) ions were performed in the 4.2-300 K range. These studies were complemented by magnetization and specific heat measurements in the 2-100K range, which revealed that MnWO(4) crystal doped with Ni(2+) ions exhibits two phase transitions at 13.9 and 12.5K. Temperature evolution of Raman wavenumbers and linewidths revealed anomalous behaviour at low temperatures. These anomalies have been attributed to spin-phonon coupling, which appear due to onset of antiferromagnetic spin ordering. The observed anomalies extend above T(N)=13.9 K. This behaviour is consistent with the fact that MnWO(4) is a moderately magnetically frustrated material.
authors: Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wroclaw 2, Poland. m.ptak@int.pan.wroc.pl
authors: M
authors: M
authors: Ptak
authors: M
authors: M
authors: Maczka
authors: K
authors: K
authors: Hermanowicz
authors: A
authors: A
authors: Pikul
authors: J
authors: J
authors: Hanuza
mesh_terms: D006358:Hot Temperature; D007501:Iron / Q000737:chemistry*; D060328:Magnetic Phenomena; D017895:Manganese Compounds / Q000737:chemistry*; D009532:Nickel / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D011208:Powders; D013052:Spectrometry, X-Ray Emission; D013055:Spectrophotometry, Infrared; D013059:Spectrum Analysis, Raman; D013696:Temperature; D017973:Tungsten Compounds / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D017895:Manganese Compounds; D010087:Oxides; D011208:Powders; D017973:Tungsten Compounds; C027424:manganese oxide; D009532:Nickel; D007501:Iron