Messi Biology states that the application of magnesium oxide (MgO) in magnetic materials has evolved from a traditional “auxiliary additive” to a key material for modulating magnetic properties, enhancing stability, and expanding functional boundaries. Through structural control, doping modification, and interface engineering, MgO is driving the development of magnetic materials towards high frequency, high density, and adaptation to extreme environments.
Its applications can be summarized in the following five aspects:
01 Core Raw Material and Performance Optimizer for Soft Ferrites
- Mechanism of Action: Magnesium oxide is the main magnesium source for manganese-zinc ferrites and nickel-zinc ferrites. It participates in the formation of the spinel structure, regulates grain size and magnetic domain distribution, thereby improving magnetic permeability and reducing hysteresis loss.
- Measured Results: Adding an appropriate amount of MgO to manganese-zinc ferrite can increase the magnetic permeability to over 15,000, making it suitable for high-frequency transformers and inductor cores.
02 Paramagnetism of Nanoscale Magnesium Oxide and Application in Magnetic Sensors
- Characteristics: Nanoscale magnesium oxide exhibits weak paramagnetism (macroscopic crystals are non-magnetic) due to surface defects and quantum size effects, and can be used to prepare high-sensitivity magnetic sensors.
- Cutting-Edge Advances: By doping with transition metals (such as Co, Ni), the magnetic susceptibility of nanoscale MgO can be increased by 2-3 orders of magnitude, making it suitable for low-temperature magnetic detection (such as medical MRI or navigation systems).
03 Spintronics and High-Density Storage Materials
- Breakthrough Point: Doped MgO (such as CoMgO thin films) can produce high spin polarization, becoming the core material for MRAM (Magnetoresistive Random Access Memory). Its switching speed is 10 times faster than traditional materials, and energy consumption is reduced by 50%.
- Application Case: IBM has tested the use of MgO-based spin valves in 100TB hard drives, with data density breaking through 10 Tbit/in².
04 Interface Modulation of Composite Magnetic Materials
- Functional Design: In hard/soft composite magnetic materials (such as BaFe₁₂O₁₉/MgO), MgO acts as an isolation phase to suppress magnetocrystalline coupling and reduce eddy current losses, making it suitable for high-frequency microwave devices (such as 5G base station filters).
- Performance Modulation: By adjusting the MgO content (5-20 wt%), the coercivity of the composite material can be reduced from 5 kOe to 1 kOe, achieving a wide range of adjustable magnetic properties.
05 Corrosion Resistance and High-Temperature Magnetic Devices
- Protective Effect: Magnesium oxide coatings can improve the oxidation resistance of magnetic alloys (such as SmCo₅), maintaining stable magnetic properties at high temperatures of 300℃, making them suitable for aerospace motors.
- Process Innovation: Through magnetic field-assisted plasma electrolytic oxidation (PEO) technology, the porosity of the MgO coating is reduced by 80%, and the corrosion current density is reduced by an order of magnitude.
06 Future Prospects
- Quantum Computing: MgO-doped qubits (quantum bits) have a low de-coherence rate and may become candidate materials for quantum magnetic storage.
- Flexible Magnetic Devices: Nanoscale MgO/polymer composite thin films can be used for wearable magnetic sensors, maintaining a magnetic response sensitivity of over 90% under bending conditions.