title: Effects of Al substitution and thermal annealing on magnetoelectric Ba0.5Sr1.5Zn2Fe12O22 investigated by the enhancement factor of 57Fe nuclear magnetic resonance.
abstract: The magnetoelectric properties of hexaferrite Ba0.5Sr1.5Zn2Fe12O22 are significantly improved by Al substitution and thermal annealing. Measuring the enhancement factor of 57Fe NMR, we found direct microscopic evidence that the magnetic moments of the L and S blocks are rotated by a magnetic field in such a way as to increase the net magnetic moment of a magnetic unit, even after the field is removed. Al substitution makes magnetoelectric property arise easily by suppressing the easy-plane anisotropy. The effect of thermal annealing is to stabilize the multiferroic state by reducing the number of pinning sites and the electron spin fluctuation. The transverse conic structure gradually changes to the alternating longitudinal conic structure where spins fluctuate more severely.
authors.affiliation: Department of Physics, KAIST, Daejeon 305-701, Republic of Korea.
authors.forename: Sangil
authors.initials: S
authors.lastname: Kwon
authors.forename: Byeongki
authors.initials: B
authors.lastname: Kang
authors.forename: Changsoo
authors.initials: C
authors.lastname: Kim
authors.forename: Euna
authors.initials: E
authors.lastname: Jo
authors.forename: Soonchil
authors.initials: S
authors.lastname: Lee
authors.forename: Yi Sheng
authors.initials: YS
authors.lastname: Chai
authors.forename: Sae Hwan
authors.initials: SH
authors.lastname: Chun
authors.forename: Kee Hoon
authors.initials: KH
authors.lastname: Kim
mesh_terms: D000535:Aluminum / Q000737:chemistry*; D001464:Barium / Q000737:chemistry; D004560:Electricity; D005290:Ferric Compounds / Q000737:chemistry*; D007504:Iron Radioisotopes / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008280:Magnetics; D008958:Models, Molecular; D013324:Strontium / Q000737:chemistry; D013696:Temperature; D015032:Zinc / Q000737:chemistry
chemical_list: D005290:Ferric Compounds; D007504:Iron Radioisotopes; C001215:ferrite; D001464:Barium; D000535:Aluminum; D015032:Zinc; D013324:Strontium