AVS 57th International Symposium & Exhibition
    Thin Film Thursday Sessions
       Session TF-ThM

Paper TF-ThM1
Thermodynamics of Clustering and Magnetism in Ti1-xAlxN and Ti1-xCrxN Thin Film Materials from First-Principles

Thursday, October 21, 2010, 8:00 am, Room Ruidoso

Session: Modeling and Analysis of Thin Films
Presenter: B. Alling, Linköping University, Sweden
Authors: B. Alling, Linköping University, Sweden
I.A. Abrikosov, Linköping University, Sweden
L. Hultman, Linköping University, Sweden
Correspondent: Click to Email

Multinary nitride materials are widely used as coatings for wear protection of cutting tools, e.g. TiAlN, as well as in thin film electronic applications. One important aspect of the success of TiAlN is a composition dependent thermodynamically driven age-hardening process through spinodal decomposition into TiN and cubic AlN at cutting tool operational temperatures. To understand this phenomena and to be able to tailor optimal compositions for different applications, we perform a thorough theoretical thermodynamics investigation based on first principles calculations.

By mapping the complete quantum mechanical complexity of the system onto a generalizes Ising Hamiltonian for the configuration of Ti and Al atoms, we are able both to predict thermodynamics using accurate Monte Carlo simulations and achieve a deeper understanding of the interactions governing the system.

One physical property that is difficult to find in nitrides and which disfavors the usage of the materials class in spintronics, is room temperature ferromagnetism. TiCrN is one of the rare nitride systems where strong ferromagnetism is seen. We use our methodological framework to analyze and explain why the magnetic interactions that favor anti-ferromagnetism in pure CrN is changed in the TiCrN solid solution, as well as the intricate dependence of the Curie temperature on the CrN content.