Multiferroic Thin Film Material that Controls Magnetization and Ferroelectricity at Room Temperature

Iron in SrTiO₃ Thin Films Is Useful in Electromagnetic and Microwave Tunable Applications

This multiferroic thin film material controls magnetization and ferroelectricity at room temperature by substituting strontium (Sr) ions with iron (Fe) ions in SrTiO₃ thin films. With applications within the micro-electromechanical system (MEMS) and radio frequency (RF)/microwave system market, multiferroic thin film materials are expected to attract significant commercial interest. The global MEMS market is expected to grow at an annual rate of 12.3 percent through 2019. As the rate of MEMS and RF/microwave applications increases in automotive and consumer electronics and in industrial and healthcare sectors, so will the demand for next generation multiferroic thin films. Available multiferroic thin films require multiple structure phase transitions using piezoelectric materials, while their high frequency properties, such as loss tangent, and response time, etc. are not very promising. This prevents such films from being used for high frequency applications. Researchers at the University of Florida have created iron substituted SrTiO₃ thin films that allow the formation of single phase multiferroic structures and that control magnetization and ferroelectricity at room temperature with very low dielectric loss and high magnetodielectric coefficients. This improvement has the potential to meet the increasing demand for multiferroic thin films in RF/microwave and MEMS applications.

Application

Multiferroic thin film material that controls magnetization and ferroelectricity at room temperature for RF/microwave and MEMS applications.

Advantages

• Substitutes iron, allowing for single phase transitions at room temperature
• Utilizes metal-insulator-metal multiferroic capacitor, operating in the microwave frequencies between 10 MHz and 5 GHz

Technology

Commonly used ABO3-type structures of multiferroic materials are limited to exhibiting sequential structure phase transitions. By substituting part of Sr with iron in SrTiO₃ thin films, researchers at the University of Florida have developed multiferroic materials exhibiting single crystal multiferroic structures at room temperature. Material dielectric loss is low and the electromagnetic coupling is high in the high frequency range, which makes the material extremely useful for RF/microwave and MEMS applications. Experimental results indicate that iron substituted multiferroic thin films control magnetization and ferroelectricity at room temperature.