CAREER: Ferromagnetic Half Metals by Design

University Of California-Santa Barbara, Santa Barbara CA

Investigators

Abstract

Ferromagnetic half metals are materials with completely spin-polarized conduction bands. Electrons in such materials are able to serve as carriers of information in electronic devices which manipulate electron spin, rather than charge. This proposal addresses rational guidelines for half metallic ferromagnetism based on the relations between chemical synthesis, crystal structure, magnetic properties, and electronic structure of inorganic materials. It is anticipated that the research will lead to a better understanding of known ferromagnetic half metals, as well as to the development of new materials showing this useful property. The proposal closely links research and education with efforts aimed at the larger community. Graduate and undergraduate researchers will be trained in the preparation and characterization of magnetic materials, and in carrying out and interpreting density functional calculations of the electronic structure. The notion that advanced materials can be designed rationally will form the foundation of a comprehensive materials chemistry curriculum. School students will be linked up with the PI's research through video mail in a program that has already been initiated. The electrons that conduct electricity in materials have two important properties. The first is charge, which enables them to carry a current. The second is a property called spin which is at the basis of some materials being magnetic. Increasingly, researchers are trying to use this second property, namely spin, in a new kind of electronics called spintronics. A spintronic circuit would be able to store information and compute faster than a normal electronic circuit. Associated with this completely novel technology is the need for new and unprecedented materials, including new kinds of magnets called half metals which would generate and sustain spin information more efficiently. While half metals have been known for about two decades, rules for making them are obscure: it is not clear why some magnets are half metals while others are not. This proposal will address this question by studying known half metals, and will come up with guidelines for making new ones, not previously known. The proposal emphasizes training undergraduate and graduate students to use the most current techniques of materials chemistry to make materials for next generation electronic devices. New and innovative ways of communicating the results of the research to school students using video mail have already been initiated.