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Weakly ferromagnetic microspheres bearing paramagnetic CrBO 3 core and nonmagnetic polyvinylbutyral shell
Author(s) -
Öztürk Ö. F.,
Tanyolac D.,
Özcan S.,
ZümreogluKaran B.
Publication year - 2009
Publication title -
polymers for advanced technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.61
H-Index - 90
eISSN - 1099-1581
pISSN - 1042-7147
DOI - 10.1002/pat.1368
Subject(s) - materials science , paramagnetism , ferromagnetism , magnetometer , particle size , antiferromagnetism , magnetism , particle (ecology) , saturation (graph theory) , composite material , analytical chemistry (journal) , condensed matter physics , chemical engineering , magnetic field , oceanography , geology , physics , mathematics , chemistry , chromatography , quantum mechanics , combinatorics , engineering
A new class of core–shell microspheres was prepared through a modified solvent evaporation technique by coating chromium orthoborate (CrBO 3 ) particles with a commercial resin, namely Mowital®B30HH (polyvinyl butyral, PVB). Well‐shaped spherical particles were obtained in diameters ranging from 40 to 420 µm. The morphological, structural, thermal, and magnetic properties were characterized by SEM, FTIR, UV–Vis, VSM (Vibrating Sample Magnetometry), and thermal analysis techniques. Uncoated CrBO 3 is paramagnetic at room temperature and antiferromagnetic at low temperatures ( T N = 12 K) while PVB itself is nonmagnetic at room temperature. The results indicated that the microspheres having a paramagnetic core and nonmagnetic shell displayed weakly ferromagnetic properties at room temperature. The observed ferromagnetism was correlated with the particle size and higher saturation magnetization values were achieved with smaller microspheres. This unconventional magnetic behavior can be tuned by varying the particle size and may allow CrBO 3 /PVB microspheres to serve as a smart material in future applications. Copyright © 2009 John Wiley & Sons, Ltd.