Operating Shock Analysis of a Thermally Assisted Magnetic Recording Head Gimbal Assembly Considering the Thermal Effects During Writing to Record the Data

Thermal Behavior of Frictional Properties on Ultra-Thin Perfluoropolyether Lubricant Film

“…As can be seen from the table, the coefficient of thermal expansion of BK7 is 7.1 × 10 -6 / K, whereas that of synthetic silica is 0.55 × 10 -6 / K. In comparison, the coefficient of thermal expansion of the magnetic disk is 14.7 × 10 -6 / K [9], which is Fig. 10 Optical microscope images of glass pin surface before test, after test, and after solvent rinse Material BK7 Fused silica Disk [10] Refractive index Table 1 Material properties of glass pin and magnetic layer [10] approximately twice that of BK7. In addition, the thermal conductivity of BK7 is almost the same as that of synthetic silica; however, the thermal conductivity of the disk is approximately three times that of synthetic silica [10].…”

“…Peng et al simulated the thermal deformation of a laser-irradiated disk surface in their study of HAMR, and they reported that when the disk surface was heated to 600 K by laser irradiation, the disk exhibited thermal expansion in the form of a 1.5-nm-high protrusion [9]. Kim et al performed the same calculation, and they reported that the protrusion due to thermal deformation of the disk surface at a heating temperature of 475°C was approximately 0.5 nm, and that the thermal protrusion of the head side at 100°C was approximately 5 nm [10]. In the pin-on-disk tester used in this study, laser irradiation may also have caused the deformation of the glass pin or disk surface, leading to variations in the area of the contact surface, which in turn may have affected the measurement of both the frictional force and the adhesive force.…”

“…10 Optical microscope images of glass pin surface before test, after test, and after solvent rinse Material BK7 Fused silica Disk [10] Refractive index Table 1 Material properties of glass pin and magnetic layer [10] approximately twice that of BK7. In addition, the thermal conductivity of BK7 is almost the same as that of synthetic silica; however, the thermal conductivity of the disk is approximately three times that of synthetic silica [10]. Considering the values of these coefficients of thermal expansion and thermal conductivity, if the material of the glass pin is changed to synthetic silica, the thermal expansion of the pin will decrease, and we should realize a difference in the temperature characteristics of the friction coefficient.…”