Synthesis and Characterization of Temperature Sensitive Li–Zn–Cu Ferrite

Abstract

The authors have fabricated the polycrystalline Li-Zn-Cu ferrite as a new temperature sensitive ferrite. The Li-Zn-Cu ferrite had high-frequency permeability profile and high electrical resistivity as well as the Ni-Zn-Cu ferrite for multilayered surface-mounting device such as a high-frequency chip inductor and filter. Since the new Li-Zn-Cu ferrite had both excellent high-frequency magnetic property and temperature sensitivity, it will be suitable for miniaturization of high-frequency inductive temperature sensing device. In this study, the relationship between grain size and the temperature-dependent magnetic properties of polycrystalline Li-Zn-Cu ferrite has been investigated. Three kinds of the Li-Zn-Cu ferrites sintered with Bi 2 O 3 at different temperature were synthesized, and their temperature characteristics were evaluated. The most important result obtained is as follows: as the sintering temperature rose the coarse grain increased without changing bulk density, the permeability and its temperature dependence can be enhanced by grain growth due to higher sintering temperature. Therefore, the temperature dependent permeability of the Li-Zn-Cu ferrite can be controlled by grain size only without a change of the chemical composition.

The influence of zinc ferrites nanoparticles on the thermal, mechanical, and magnetic properties of rubber nanocomposites

“…This ferrite possess unique magnetic, magneto‐optical, magneto‐resistive, thermal, electric, and mechanical properties such as ferromagnetism, excellent creep and radiation damage resistance, high thermal conductivity, high electrical resistivity, controllable saturation magnetization, moderate thermal expansion coefficients, energy‐transfer efficiency, and narrow line width in ferromagnetic resonance [19–21]. These properties make zinc ferrites suitable for numerous device applications, including magnetic materials (circulators, oscillators, and phase shifters for microwave region), sensors, magneto‐optic sensors, anode materials for batteries, catalysts, and sensors for space applications, lasers, phosphorescent sources, microwave and electrochemical devices, and black and brown pigments [22–24]. However, the ferrite in ceramic form has inherent drawback because it is not moldable or flexible to form complex shapes of products.…”

Synthesis and Characterization of Novel Nanoceramic Magnesium Ferrite Material Doped with Samarium and Dysprosium for Designing – Microstrip Patch Antenna

“…The oxide phase of Iron-containing transition metal has been the subject of extensive investigations. These oxides posses unique magnetic, magneto-optical, magneto resistive, thermal, electric and mechanical properties such as ferromagnetism, excellent creep and radiation damage resistance, high thermal conductivity, high electrical resistivity, controllable saturation magnetization, moderate thermal expansion coefficients, energy-transfer efficiency, narrow line width in ferromagnetic resonance and others [1][2][3][4][5].…”

Basic investigation of microtemperature sensor by means of a novel transmission-line technique using a temperature-sensitive Li–Zn–Cu ferrite substrate

“…It was considered that the magnetic loss m 00 of ferrite enhanced the distributed resistance. Since m 00 was already started rising at 10-100 MHz region, the natural resonance frequency of the ferrite should be made higher from the l/4 resonance frequency by a modification of the ferrite composition or microstructure [5]. The ignored dielectric loss of ferrite may influence Q because it is larger than that of polymer capacitor.…”

“…Recently, the authors investigated the temperature dependence of magnetic properties of Li-Zn-Cu ferrite [5], and found that its complex permeability exhibits remarkable temperature dependence in a wide temperature range from À35 to 125 1C. It was considered that Li-Zn-Cu ferrite has large temperature coefficient of magnetic anisotropy because this ferrite has no Fe 2+ and high Curie temperature over 400 1C [5]. Furthermore, its temperature dependence of permeability corresponds to simple exponential function.…”