Home | About Us | FAQ | Courses | Contact Us |  Sign-In
Syllabus  |   Lectures  |   Downloads  |   FAQ  |   Ask a question  |  
Course Co-ordinated by IIT Guwahati
Question in Lecture
Ask a Question

Question Topics :

NOTE: Before you post question check if your question already exists.Please do not repeat questions.

All Questions

Question: Respected sir,in one of the recent physics letters i came acoss \"skyrmion particles\". These particles are proposed to be information carriers in spintronics because of their intrinsic properties such as stability against structure distortions. Sir could you explain me what are these skyrmions?
By: Showkat Mir     Date: 2013-03-17

Answer: Dear Showkat Mir, Thanks for your query and sorry for my late answer. Well, skyrmion particles are hypothetical particles related to baryons (including protons and neutrons). These baryons are made up of three quarks in the standard model. I hope now you got the picture of the skyrmion. Unfortunately, they are not yet conclusively proven. One of the problems in going down below the atomic level for storing information or information carrier is the stability against the temperature (even at room temperature). Unless, all the characteristics of the skyrmion is realized, it is not easy to visualize their applicability. Regards, perumal

By: Dr. A. Perumal     Email: mirshowkat07@gmail.com     Date: 2013-04-05

Question: respected Sir, I want to know that how spin orbit coupling leads to anisotropic magneto resistance(AMR).
By: Atul Tiwari     Date: 2014-05-16

Answer: Dear Atul, Thanks for your query. As you know well that the AMR is property of a material in which a dependence of electrical resistance on the angle between the direction of electric current and direction of magnetization is observed. The variation of resistance in the materials is different when the magnetic field is applied parallel and perpendicular to electrical current. The effect arises from the simultaneous action of magnetization (affected by the applied field) and spin-orbit interaction. The general spin-orbit interaction has the form of The spin-orbit interaction has the form H(SO) = K L.S provided the electrostatic potential is radial. This makes a contribution to the energy of the d states that depends on spin and magnetization direction, making it favorable for the magnetization to point along certain crystallographic directions. In this case, the d electron spin is coupled to its orbital motion, which in turn is coupled to the lattice by the crystal field. Therefore, both spin-orbit and magnetization contributes to AMR. A nice review article is published in this regard by McGuire et al, IEEE Trans Magn 11 (1975) 1018. You would get a clear picture when you go through the article. Feel free to discuss with me if you need any further details.

By: Dr. A. Perumal     Email: atul.tiwari17@gmail.com     Date: 2014-08-05
Disclaimer: We will take every effort to answer your question.However, in case of delay or no response NPTEL claims no responsibility.

Site Maintained by Web Studio, IIT Madras. Contact Webmaster: nptel@iitm.ac.in