Magnetic phase diagram of magnetoelectric LiMnPO4

TitleMagnetic phase diagram of magnetoelectric LiMnPO4
Publication TypeJournal Article
Year of Publication2012
AuthorsToft-Petersen R, Andersen NH, Li HF, Li JY, Tian W, Bud'ko SL, Jensen TBS, Niedermayer C, Laver M, Zaharko O, Lynn JW, Vaknin D
Journal TitlePhysical Review B
Date Published06
Type of ArticleArticle
ISBN Number1098-0121
Accession NumberWOS:000305251300004
KeywordsANTIFERROMAGNET, ferroelectricity, scattering, SINGLE-CRYSTAL, spin-flop, tetracritical points, weak ferromagnetism

The nature of the spin-flop (SF) transition in the magnetoelectric quasi-2D Heisenberg system LiMnPO4 is studied in fields applied along the a axis. A refinement of the magnetic structure using neutron diffraction data in the SF phase reveals that the spins reorient from being parallel to the a axis to be nearly along the c axis at magnetic fields between 4 and 4.7 T, depending on temperature. The low-field antiferromagnetic phase boundary is shown to join the spin-flop line tangentially at the so-called bicritical point, where there is a suppression of the ordering temperature. At the bicritical field, we observe an increased intensity of the Lorentz broadened elastic scattering at magnetic Bragg peaks above T-N as compared to zero field and 10 T, without an increase in peak width. This suggests an increased density of fluctuations at the bicritical field as compared to zero field.

URL<Go to ISI>://WOS:000305251300004
Alternate JournalPhys. Rev. B