The Mn effect on magnetic structure of FeMn-B amorphous metals
- PDF / 270,005 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 17 Downloads / 150 Views
MM5.17.1
The Mn effect on magnetic structure of FeMn-B amorphous metals Yang Wang1, D.M.C. Nicholson2, M. Widom3, M. Fuentes-Cabrera2,3, and M. Mihalkovic3 1 Pittsburgh Supercomputing Center, Carnegie Mellon University, Pittsburgh, PA 15213 2 Computational Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 3 Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213
ABSTRACT Fe-rich Fe-B amorphous metals exhibit approximately collinear magnetic structure. When a certain amount of Fe atoms are replaced with Mn, the magnetic structure of the alloys is found to become non-collinear. We performed electronic structure calculations using the locally selfconsistent multiple scattering (LSMS) method for supercell samples generated by ab initio molecular dynamics simulation using the Vienna Ab-initio Simulation Package (VASP). We present the distribution of moment sizes and angular distributions in the FeMn-B amorphous metal samples. We discuss the Mn effect on the magnetic structure of the alloys.
INTRODUCTION Amorphous metals, also known as metallic glasses, differ from ordinary metals in that their constituent atoms are not arranged on a crystalline lattice. Because of this, they exhibit unique combinations of physical properties [1,2]. Until recently, they have largely been manufactured in the form of thin ribbons usually less than 1mm in thickness, because a fast cooling rate is (~ 106 K/sec) required for retaining the metastable amorphous phase. In contrast, the bulk amorphous metals are made with conventional cooling methods. Since they were first discovered in the early 1980s [3,4], the bulk amorphous metals have attracted much attention from researchers for their properties such as low volume shrinkage, high mechanical strength and hardness, low surface roughness, and possibly high resistance to corrosions. (See reference [5] for a historical summary on the discovery of bulk amorphous metals.) They have been proposed for a range of potential applications in sporting goods materials, medical and dental implants, machining tools, coatings, and more. Recently, a number of Fe-based bulk amorphous metals have been made in laboratory. In addition to the mechanical properties we just mentioned, they show some unique magnetic properties such as high saturation magnetization and high permeability, which make them a good candidate for magnetic core materials in transformers and electric motors. Lately, high Mn content, Fe-based bulk amorphous metals have been investigated by Poon et al as prospective amorphous steels [6]. These are non-ferromagnetic structural amorphous metals with magnetic transition temperatures far below the ambient temperature. To understand the Mn effect on the magnetic structure of Fe-based amorphous metals, we carried out theoretical investigation of the Fe0.8−xMnxB0.2 alloys using ab initio electronic structure calculation techniques. We determined the magnetic structure of the alloys for Mn contents ranging from 0 to 80 percent. A detailed description of our theoreti
Data Loading...
