Self-Heating Modeling of Magnetic Recording Read Head

2005 ◽  
Author(s):  
Y. Yang ◽  
L. Baril ◽  
E. Schreck ◽  
A. Wallash ◽  
M. Asheghi
Keyword(s):  
Magnetic Recording ◽  
Temperature Rise ◽  
Areal Density ◽  
Technical Conference ◽  
Normal Operation ◽  
Electronic Systems ◽  
Element Analysis ◽  
Self Heating ◽  
Read Head ◽  
Gmr Sensor

The performance and reliability of the GMR heads are adversely affected by self-heating due to the aggressive scaling of its dimensions to increase areal density. In this manuscript, the self-heating of the GMR head during the normal operation is investigated. An analytical model is developed to estimate the temperature rise in the GMR sensor due to self-heating for magnetic recording areal densities from 2.8 to 80 Gbits/in2, which agrees well with the FEM simulations. This model is subsequently used to investigate the influence of the GMR head constituent materials’ thermal properties on the device temperature rise. A 3-D finite element analysis was also performed to predict the level of self-heating in lead-overlaid (LOL) design, which agrees well with the experimental data obtained using steady-state and transient measurements.   This paper was also originally published as part of the Proceedings of the ASME 2005 Pacific Rim Technical Conference and Exhibition on Integration and Packaging of MEMS, NEMS, and Electronic Systems.

Analysis and Mitigation of Sample Heating in Thermoreflectance Microscopy

2005 ◽  
Author(s):  
Andrew C. Miner ◽  
Uttam Ghoshal
Keyword(s):  
Heat Flux ◽  
Temperature Field ◽  
Temperature Rise ◽  
Technical Conference ◽  
Electronic Systems ◽  
Sample Heating ◽  
Large Measurement ◽  
Reflectance Microscopy ◽  
Analytical Expressions ◽  
Thermoreflectance Microscopy

The illumination of a sample when imaged by thermoreflectance thermal microscopy may cause significant heating of the surface. Nonlinearities in the performance of the system being imaged may lead to large measurement induced errors in the observed temperature field. Analytical expressions are presented to estimate the temperature rise and heat flux in a sample. Spatially filtered thermo-reflectance microscopy is introduced as a technique to significantly reduce the incident heat flux without loss of spatial resolution.   This paper was also originally published as part of the Proceedings of the ASME 2005 Pacific Rim Technical Conference and Exhibition on Integration and Packaging of MEMS, NEMS, and Electronic Systems.

Thermal Characterization of the 144 nm GMR Layer Using Microfabricated Suspended Structures

2003 ◽  
Author(s):  
Shu Zhang ◽  
Yizhang Yang ◽  
Sadegh M. Sadeghipour ◽  
Mehdi Asheghi
Keyword(s):  
Temperature Rise ◽  
Electrostatic Discharge ◽  
Thermal Characterization ◽  
Normal Operation ◽  
Maximum Temperature ◽  
Multilayer Structures ◽  
Accurate Knowledge ◽  
Gmr Sensor ◽  
Present Effort

The performance and reliability of GMR heads are influenced by the level of temperature rise, which may occur in the device during the normal operation or during an electrostatic discharge (ESD) event. However, the reliable electro-thermal modeling of the GMR sensor to predict the temperature rise, demands an accurate knowledge of the thermal properties of its constituent materials such as Al2O3 passivation and GMR layers. The lateral thermal conductivity of the GMR layer, which has not been measured previously, can largely influence the maximum temperature rise in the GMR sensor. The present effort will be directed at thermal characterization of the CoFe/Cu multilayer structures made of extremely thin periodic layers, using steady-state and frequency domain heating and thermometry in suspended bridges. The measurements are performed on several suspended structures with the lengths and widths in the range of 250 to 500 μm and 16 to 20 μm, respectively.

Modeling of Temperature Rise in Giant Magnetoresistive (GMR) Sensor During an Electrostatic Discharge (ESD) Event

2003 ◽  
Author(s):  
Yizhang Yang ◽  
Sadegh M. Sadeghipour ◽  
Mehdi Asheghi
Keyword(s):  
Thermal Properties ◽  
Temperature Rise ◽  
Electrostatic Discharge ◽  
Thermal Response ◽  
Human Body Model ◽  
Element Analysis ◽  
Current Voltage ◽  
Source Current ◽  
Reliability Issue ◽  
Gmr Sensor

With the further miniaturization of the GMR heads, the electrostatic discharge (ESD) failure has become the primary reliability issue in manufacturing of these sensors. The Joule heating effect during the ESD events result in both thermal and magnetic damages in GMR heads. In this paper, the thermal response of the GMR read head to the excessive current/voltage during an ESD event is investigated numerically using a 3-D finite element analysis. Unlike the previous studies, the thermal properties of the GMR and Al2O3 gap layers used in the simulation are the experimentally measured values. The temperature-rise in GMR heads under human-body-model (HBM) source current is obtained for a range of GMR dimensions and thermal properties of its constituent materials. The simulation results show that temperature in the GMR element sharply increases as the GMR dimensions are reduced, indicating the future GMR heads are more susceptible to the ESD damages. In addition, thermal properties of the GMR and gap materials play key roles in accurate prediction of the temperature field in GMR head during ESD events.

Thermo-Mechanical Modeling and Analysis of Equal Channel Angular Pressing

2005 ◽  
Vol 23 ◽  
pp. 263-266 ◽  
Author(s):  
Qing Xiang Pei ◽  
B.H. Hu ◽  
C. Lu
Keyword(s):  
Equal Channel Angular Pressing ◽  
Temperature Rise ◽  
Flow Behavior ◽  
Material Model ◽  
Workpiece Material ◽  
Element Analysis ◽  
Modeling And Analysis ◽  
Die Geometry ◽  
Angular Pressing ◽  
Good Agreement

Thermo-mechanical finite element analysis was carried out to study the deformation behavior and temperature distribution during equal channel angular pressing (ECAP). The material model used is the Johnson-Cook constitution model that can consider the multiplication effect of strain, strain rate, and temperature on the flow stress. The effects of pressing speed, pressing temperature, workpiece material and die geometry on the temperature rise and flow behavior during ECAP process were investigated. The simulated temperature rise due to deformation heating was compared with published experimental results and a good agreement was obtained. Among the various die geometries studied, the two-turn die with 0° round corner generates the highest and most uniform plastic strain in the workpiece.

Head Instability Detection for Testing Process in Perpendicular Magnetic Recording System

2013 ◽  
Vol 770 ◽  
pp. 319-322 ◽  
Author(s):  
Piya Kovintavewat ◽  
Santi Koonkarnkhai ◽  
Aimamorn Suvichakorn
Keyword(s):  
Magnetic Recording ◽  
Signal To Noise Ratio ◽  
Disk Drive ◽  
Detection Algorithm ◽  
Recording System ◽  
High Signal ◽  
Signal To Noise ◽  
Perpendicular Magnetic Recording ◽  
Read Head ◽  
Pass Through

During hard disk drive (HDD) testing process, the magneto-resistive read (MR) head is analyzed and checked if the head is defective or not. Baseline popping (BLP) is one of the crucial problems caused by head instability, whose effect can distort the readback signal to the extent of causing possible sector read failure. Without BLP detection algorithm, the defective read head might pass through HDD assembling process, thus producing an unreliable HDD. This situation must be prevented so as to retain customer satisfaction. This paper proposes a simple (but efficient) BLP detection algorithm for perpendicular magnetic recording systems. Results show that the proposed algorithm outperforms the conventional one in terms of both the percentage of detection and the percentage of false alarm, when operating at high signal-to-noise ratio.

Transient Thermal Response of the Media by Free Space Laser Heating in Heat Assisted Magnetic Recording

2016 ◽  
Author(s):  
Shaomin Xiong ◽  
Robert Smith ◽  
Na Wang ◽  
Dongbo Li ◽  
Erhard Schreck ◽  
...  
Keyword(s):  
Magnetic Recording ◽  
Heat Conduction Problem ◽  
Temperature Response ◽  
Thermal Response ◽  
Areal Density ◽  
Heat Assisted Magnetic Recording ◽  
Lumped Model ◽  
The Media ◽  
Transient Thermal ◽  
Transient Thermal Response

Heat assisted magnetic recording (HAMR) promises to deliver higher storage areal density than the current perpendicular magnetic recording (PMR) product. A laser is introduced to the HAMR system to heat the high coercively magnetic media above the Curie temperature (Tc) which is as high as 750 K in order to enable magnetic writing. The thermal response of the media becomes very critical for the success of the data writing process. In this paper, a new method is proposed to understand the transient thermal behavior of the HAMR media. The temperature response of the media is measured based on thermal erasure of the magnetically written signal. A lumped model is built to simplify the heat conduction problem to understand the transient thermal response. Finite element modeling (FEM) is implemented to simulate the transient thermal response of the media due to the laser pulse heating. The experimental and simulation results show fairly good agreement.

Research on the Anti-Vibration Technology of Large Cross-Section Conductor

2013 ◽  
Vol 457-458 ◽  
pp. 522-526
Author(s):  
Jun Zhang ◽  
Kuan Jun Zhu ◽  
Zhen Liu ◽  
Xue Ping Zhan
Keyword(s):  
Cross Section ◽  
Performance Test ◽  
Power Transmission ◽  
Normal Operation ◽  
Large Cross Section ◽  
Element Analysis ◽  
Test Analysis ◽  
Vibration Effect ◽  
The Finite Element Analysis ◽  
Vibration Technology

The conductor is an important part of the process of power transmission. Keep conductor to be normal operation is an important link of power transmission. In practice, Due to the influence of many weather environments, such as wind, temperature, rain and snow, the conductor often appear ice disaster, dance and other disasters; therefore, the anti-vibration technology of conductor is an urgent need to develop. This paper masters the performance of damper by carrying out a great deal of performance test analysis, such as self-damping, the power of damper, anti-vibration effect. At the same time, this paper understands the effect of spacer arrangement on the sub span oscillation, through the finite element analysis and lingo program of nonlinear programming, laying the foundation for studying anti-vibration technology for large cross-section conductor.

scholarly journals Numerical Evaluation and Experimental Test on a New Giant Magnetostrictive Transducer with Low Heat Loss Design

Micromachines ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1397
Author(s):  
Zhuan Bai ◽  
Zonghe Zhang ◽  
Ju Wang ◽  
Xiaoqing Sun ◽  
Wei Hu
Keyword(s):  
Heat Loss ◽  
Temperature Rise ◽  
Magnetic Energy ◽  
Mechanical Energy ◽  
Electric Energy ◽  
Energy Utilization ◽  
Element Analysis ◽  
Excessive Heat ◽  
Excitation Coil ◽  
Magnetostrictive Transducer

Giant magnetostrictive transducer with micro and nano precision has a wide application prospect in the field of remote sensing. However, excessive heat loss of components could generate during the energy conversion and transfer from electric energy to magnetic energy, and magnetic energy to mechanical energy, thereby affecting its long-term service and also reducing energy utilization. In this paper, a new magnetostrictive transducer is proposed and its excitation coil, internal and external magnetic circuit are optimized from the perspective of reducing heat loss. With the help of theoretical and finite element analysis, the response law between key parameters and heat loss of key components are summarized, which provides a basis for reducing heat loss. Finally, according to the optimization scheme, the prototype is processed, and the temperature rise and dynamic output performance of the transducer are tested by constructing an experimental setup. The results show that the transducer has a low temperature rise and good frequency response characteristics, which can provide support for long-time precise actuation on-orbit.

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