Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Magnetic and Electric Properties
Name: Ravi
Status: other
Grade: other
Location: IL



Question:
1. Can we correlate magnetic properties of materials with electrical properties? i.e. If the material is insulator, will it have specific magnetic properties(paramagnetic or diamagnetic or ferromagnetic).

2. Is it possible for a conductor the surface layer can be insulating(not because of chemical reactions takes place on the surface) and the other layers can be conducting? If so how can we identify a material as a conductor or insulator?


Replies:
Hi Ravi,

To answer your first question, there is no specific correlation between magnetic and electrical properties of materials. Permanent magnets, for example can be electrically conducting (such as those made of ALNICO, or steel), or they can be electrical insulators (such as ceramic magnets used on most speakers, refrigerator magnets and so on). Both these (one, an insulator and the other a conductor) exhibit the same ferromagnetic properties.

Answering your second question, I am unaware of any contiguous material that has conductance throughout its bulk, but is an insulator on its surface. Of course this can be achieved chemically, for example when the surface of aluminum is oxidized by the process known as anodization. Similarly, one could imagine a lump of graphite (a conductor) whose surface was somehow converted to a thin layer of diamond (an insulator), even though these are both just allotropes of plain carbon. But I believe this sort of thing is not what you were referring to. If a material is contiguous throughout, it is hard to imagine how the atoms or molecules of that material would "know" they were close to the surface, and therefore should change somehow from a conductor to an insulator.

Regards,
Bob Wilson.



Click here to return to the Material Science Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (help@newton.dep.anl.gov), or at Argonne's Educational Programs

NEWTON AND ASK A SCIENTIST
Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory