Magnetic material for antennas, antenna, and wireless communication device

摘要

A magnetic material for antennas including: an M-type hexagonal ferrite represented by the following general formula (1) as a main phase, MA.Fe12-x.MBx.O19 (wherein MA is at least one kind selected from the group consisting of Sr and Ba, MB is MC or MD, MC is at least one kind selected from the group consisting of Al, Cr, Sc and In, MD is an equivalent mixture of at least one kind selected from the group consisting of Ti, Sn and Zr and at least one kind selected from the group consisting of Ni, Zn, Mn, Mg, Cu and Co, X is a number from 1 to 5), and an average crystal particle diameter is equal to or greater than 5 μm.

主权项

1. A magnetic material for antennas, comprising:
a M-type hexagonal ferrite represented by the following general formula (1) as a main phase:
MA.Fe12-x.MBx.O19  (1) where MA is at least one selected from the group consisting of Sr and Ba,
MB is MC or MD,MC is at least one selected from the group consisting of Al, Cr, Sc and In,MD is an equivalent mixture of at least one selected from the group consisting of Ti, Sn and Zr and at least one selected from the group consisting of Ni, Zn, Mn, Mg, Cu and Co,X is a number from 1 to 5; and at least one compound selected from the group consisting of 0.1-3% by mass of SiO2, 0.5-5% by mass of CaO, and 0.5-8% by mass of Bi2O3, wherein an average crystal particle diameter of a sintered compact sample surface of the magnetic material after etching by concentrated hydrochloric acid is equal to or greater than 20 μm as determined by observation with a scanning electron microscope, and a natural resonance frequency f0(n) of the magnetic material is configured to be equal to or greater than 5 GHz and a magnetic domain wall resonance frequency f0(d·w) of the magnetic material is configured to be equal to or smaller than 0.8 GHz.