Navigation Links
Size matters in the giant magnetoresistance effect in semiconductors
Date:10/19/2013

In a paper appearing in Nature's Scientific Reports, Dr. Ramesh Mani, professor of physics and astronomy at Georgia State University, reports that a giant magnetoresistance effect depends on the physical size of the device in the GaAs/AlGaAs semiconductor system.

Giant magnetoresistance indicates a large change in the electrical resistance with the application of a small magnetic field. This effect can be used to detect the presence of small magnetic fields. Magnetic sensors based on this concept are used to read out information stored in magnetic particles on rotating platters in computer hard disks. Other types of magnetic sensors are also used in brushless electric motors within cooling fans in computers, and as wheel speed sensors in some automobiles. Semiconductors are materials with electrical characteristics that fall between those of insulators and metals. Such materials are widely used, especially in electronics.

In research that is supported by grants from the U.S. Department of Energy and the U.S. Army Research Office, Mani studied the magnetoresistance in flat, very thin sheets of electrons in the ultra high quality GaAs/AlGaAs semiconductor with his colleagues Annika Kriisa from Emory University and Werner Wegscheider from the ETH-Zurich in Switzerland.

The researchers found that the change in the resistance or resistivity with the magnetic field depends on the size of the device. They demonstrated that, under the application of a magnetic field, wide devices develop a smaller and quicker change, while small devices develop a bigger but slower change in the resistivity. The resistance or resistivity of a material to the flow of electricity is a technologically important property, especially in semiconductors.

In a typical semiconductor, the disorder is so strong that electrons undergo many collisions over a short distance - distance much less than millimeters. Then, the edges or walls of the device have no influence on measured properties because the electrons lose memory of one edge or wall by the time they get to another.

The strong sensitivity of the magnetoresistance to the size of the device observed in this research indicates that scattering with the walls of the device might be making a substantial contribution to electron scattering. This result testifies to the high quality of the semiconductor used in this research, produced by Prof. Werner Wegscheider at ETH-Zurich in Switzerland.

This research team developed a model to understand the observations and deduced that when the semiconductor system becomes of even better quality, the change in the resistance under the application of a magnetic field will become even bigger. Indeed, the change might become so big that the resistance vanishes entirely in the small magnetic field.


'/>"/>

Contact: LaTina Emerson
lemerson1@gsu.edu
404-413-1353
Georgia State University
Source:Eurekalert

Related biology technology :

1. Jeffrey Toobin Joins Gateway Public Schools for the 2013 Matters of the Mind Luncheon
2. Management Matters Series Starts with “Lab Budgeting 101”
3. EveryDayMatters.com Aims to Raise Awareness and Coordinate Care Between Mental and Physical Health
4. Express Diagnostics to Raise Funds for American Cancer Society During Blue Earth’s Giant Days Parade
5. Researchers untangle molecular pathology of giant axonal neuropathy
6. Berkeley Lab researchers use metamaterials to observe giant photonic spin hall effect
7. GLM Displays Introduces New Banner Stand – 10’ Tall “Giant Mosquito”
8. VIASPACE Chairman and CEO Attend EUEC 2013, Giant King Grass Prominently Featured in Convention Exhibit Hall
9. A giant step in a miniature world: UZH researcher measures the electrical charge of nano particles
10. Exotic particles, chilled and trapped, form giant matter wave
11. SoundConnect Responds to Increased, Cost-Effective Unified Communications Demands Through Agent Partnership Program
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:10/11/2017)... and LAGUNA HILLS, Calif. , Oct. 11, ... Research, London (ICR) and University of ... SkylineDx,s prognostic tool to risk-stratify patients with multiple myeloma (MM), ... nine . The University of Leeds ... funded by Myeloma UK, and ICR will perform the testing ...
(Date:10/11/2017)... ... October 11, 2017 , ... A new study ... in frozen and fresh in vitro fertilization (IVF) transfer cycles. The ... IVF success. , After comparing the results from the fresh and frozen transfer ...
(Date:10/10/2017)... ... October 10, 2017 , ... San Diego-based team building and ... rebranding initiative announced today. The bold new look is part of a transformation ... moves into a significant growth period. , It will also expand its service offering ...
(Date:10/10/2017)... PA (PRWEB) , ... October 10, 2017 , ... ... City Science Center’s FirstHand program has won a US2020 STEM Mentoring Award. Representatives ... the award for Excellence in Volunteer Experience from US2020. , US2020’s mission is ...
Breaking Biology Technology:
(Date:4/4/2017)... 2017   EyeLock LLC , a leader of ... States Patent and Trademark Office (USPTO) has issued U.S. ... of an iris image with a face image acquired ... company,s 45 th issued patent. ... given the multi-modal biometric capabilities that have recently come ...
(Date:3/30/2017)... , March 30, 2017 Trends, opportunities ... (physiological and behavioral), by technology (fingerprint, AFIS, iris recognition, ... recognition, and others), by end use industry (government and ... immigration, financial and banking, and others), and by region ... , Asia Pacific , and ...
(Date:3/24/2017)... Controller General of Immigration from Maldives Mr. Mohamed Anwar and ... international IAIR Award for the most innovative high security ePassport and eGates  ... ... Maldives Immigration Controller General, Mr. Mohamed Anwar ... right) have received the IAIR award for the "Most innovative high security ...
Breaking Biology News(10 mins):