Preparation And Characterization Of Co-Mn Ferrite Applied To Magneto-Elastic Receiving Device

In scientific research, sensor is an important tool for collecting data of the natural world. Especially today highly developed computer technology are highlighting sensor's importance. Sensor is an component which can be used in measuring instrument, intelligent instrument, automatic control systems, computer input devices. It is called 'the tactile of all the information'. We use variety of sensors in industry, agriculture, environmental protection, medicine, even appliances used in our daily lives.Among them, the magneto-elastic sensor which based on the magnetostrictive principle increasingly draws more and more attention. Magneto-elastic sensor has a number of advantages such as large output power, strong signal, anti-jamming performance, easy to make. So, at the same time, the choice of material applied to the receiving device of the magneto-elastic sensor becomes an issue requiring urgent solution.This article aims to find the material applicable to the receiving device. Based on studing the theory of spinel ferrite and magnetostrictive effect, we carry out a series of study such as the preparation of materials, material composition design and performance characterization. Ferrite series were prepared by layered double hydroxides (LDHs) method. As metal ions in LDHs layers can be regulated and interlayer anions can be exchanged, we add Mn²⁺,Co²⁺,Fe²⁺ and Fe³⁺ ions to LDHs layers and synthesize Co-Mn ferrite series(Co_1-xMn_xFe₂O₄). According to the structure and performance characterization of precursors and calcined products, we draw the conclusions as follows:1) Co-Mn ferrite can be synthesized by the method of LDHs layered precursors. We can get Co_1-xMn_xFeO₄ ferrite with single spinel phase when the Co²⁺+Mn²⁺/Fe²⁺/Fe³⁺ molar ratio is 5/7/3. 2) Co_1-xMn_xFeO₄ ferrite with x=0.1 had a larger saturation magnetization value than that of cobalt ferrite, and then the value decreased as Mn content increasing. The addition of Mn reduces the coercivity, and manganese content the greater the smaller the coercive force and ultimately reduces the hysteresis phenomenon of the material.3) Co_1-xMn_xFeO₄ ferrite series has a high cut-off frequency, and the frequency range being used is wide. The content of Mn²⁺ has some effect on the permeability change with temperature.4) Co_1-xMn_xFeO₄ ferrite can receive the Barkhausen signal. The sample with x=0.1 has the best reception effect. The signal intensity compared with the standard signal is still weak, the signal to noise ratio (SNR) reaches 9.6. Co_1-xMn_xFeO₄ ferrite was expected to be used in Barkhausen magneto-elastic sensors as receiving magnetic core.