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Papers by Rogelio Murillo

Research paper thumbnail of <title>Impact of mask absorber on EUV imaging performance</title>

26th European Mask and Lithography Conference, 2010

EUVL requires the use of reflective optics including a reflective mask. The reticle blank contain... more EUVL requires the use of reflective optics including a reflective mask. The reticle blank contains a reflecting multilayer, tuned for 13.5nm actinic light, and an absorber which defines the dark areas. The oblique incidence of light in combination with the small wavelength in comparison to the mask topography causes a number of effects which are unique to EUV, such as

Research paper thumbnail of Fabrication of patterned magnetic nanodots by laser interference lithography

Microelectronic Engineering, 2005

A method of fabrication of patterned magnetic nanodots by means of laser interference lithography... more A method of fabrication of patterned magnetic nanodots by means of laser interference lithography is presented. This method includes the use of a diluted positive photoresist, and modifications in the etching angle and acceleration voltage of the ion beam etching process. Vertical standing waves were suppressed by using a high exposure dose (supraexposure) instead of an antireflective coating. Field dependent magnetic force microscopy was used to measure the switching field distribution, which was found to range from 80 to 192 kA/m.

Research paper thumbnail of AHE measurements of very thin films and nanosized dots

Journal of Magnetism and Magnetic Materials, 2005

In this paper we present anomalous Hall effect analysis from very thin Co (0.5 nm) film, Co/Pt mu... more In this paper we present anomalous Hall effect analysis from very thin Co (0.5 nm) film, Co/Pt multilayers and large areas of nanosized dots as well as from a few magnetic dots having a diameter of 120 nm. The dot array is prepared from Co/Pt multilayer by using laser interference lithography (LIL) while the Hall crosses for measuring a few dots are prepared in combination with focussed ion beam (FIB). The hysteresis loops from a few dots are showing significant Hall voltage jumps corresponding to magnetic response due to an inhomogeneous reversal mechanism because the intensity of the jumps is smaller than the expected value from a total magnetization reversal of one dot.

Research paper thumbnail of Anomalous Hall-effect measurement study on Co∕Pt nanosized dot

Journal of Applied Physics, 2005

Dot arrays made of polycrystalline Co/ Pt multilayer with an average grain size of 20 nm are fabr... more Dot arrays made of polycrystalline Co/ Pt multilayer with an average grain size of 20 nm are fabricated by using a laser interference lithography and their magnetic properties are examined by detecting anomalous Hall effect. It is revealed that the ratio of dots which have stable single domain state increases from 35% to 85% while the dot diameter decreased from 200 to 120 nm. The energy barrier height of magnetization reversal is estimated as 4.0ϫ 10 −12 erg from sweep rate dependence of the coercivity. The energy corresponds to the switching volume comparable with the volume of a physical grain in the multilayer film.

Research paper thumbnail of Magnetization process of high anisotropy CoPt nanosized dots

IEEE Transactions on Magnetics, 2005

Dot arrays with diameter ranging from 80 to 245 nm are made of Co 80 Pt 20 films with large perpe... more Dot arrays with diameter ranging from 80 to 245 nm are made of Co 80 Pt 20 films with large perpendicular anisotropy. Magnetic properties are investigated by detecting the anomalous Hall effect. The all arrays show angular dependence of remanent coercivity similar to coherent rotation. The result shows that reversal process is independent of dot diameter. The energy barrier height of magnetization reversal is estimated as 1.0 10 10 erg for the array consists of 140-nm-diameter dots. From the energy value, the switching volume is estimated as equivalent to the volume of a physical grain in the film. The results indicate that the reversal process starts from a nucleation of a "reversed grain" followed by propagation process.

Research paper thumbnail of Thermal stability and switching field distribution of CoNi/Pt patterned media

Microsystem Technologies, 2006

The thermal dependence and distribution of the switching fields of arrays of magnetic Co50Ni50/Pt... more The thermal dependence and distribution of the switching fields of arrays of magnetic Co50Ni50/Pt nanodots has been studied. These dots, with a diameter of 90 nm, are arranged in a hexagonal pattern with a periodicity of 300 nm. Field-dependent magnetic force microscopy was used to measure the switching field distribution of the array, which was found to range from 80 to 192 kA/m,

Research paper thumbnail of Probe Recording in Magnetic Patterned Media

In this paper we explain why future probe storage systems will use patterned media. As a model sy... more In this paper we explain why future probe storage systems will use patterned media. As a model system, magnetic patterned media will be discussed, even though their data density is limited to about . The first results on magnetic probe storage on patterned media are presented, and the problem of switching field distribution is discussed in detail. Finally we will present the first steps into two-dimensional coding for patterned media.

Research paper thumbnail of <title>Impact of mask absorber on EUV imaging performance</title>

26th European Mask and Lithography Conference, 2010

EUVL requires the use of reflective optics including a reflective mask. The reticle blank contain... more EUVL requires the use of reflective optics including a reflective mask. The reticle blank contains a reflecting multilayer, tuned for 13.5nm actinic light, and an absorber which defines the dark areas. The oblique incidence of light in combination with the small wavelength in comparison to the mask topography causes a number of effects which are unique to EUV, such as

Research paper thumbnail of Fabrication of patterned magnetic nanodots by laser interference lithography

Microelectronic Engineering, 2005

A method of fabrication of patterned magnetic nanodots by means of laser interference lithography... more A method of fabrication of patterned magnetic nanodots by means of laser interference lithography is presented. This method includes the use of a diluted positive photoresist, and modifications in the etching angle and acceleration voltage of the ion beam etching process. Vertical standing waves were suppressed by using a high exposure dose (supraexposure) instead of an antireflective coating. Field dependent magnetic force microscopy was used to measure the switching field distribution, which was found to range from 80 to 192 kA/m.

Research paper thumbnail of AHE measurements of very thin films and nanosized dots

Journal of Magnetism and Magnetic Materials, 2005

In this paper we present anomalous Hall effect analysis from very thin Co (0.5 nm) film, Co/Pt mu... more In this paper we present anomalous Hall effect analysis from very thin Co (0.5 nm) film, Co/Pt multilayers and large areas of nanosized dots as well as from a few magnetic dots having a diameter of 120 nm. The dot array is prepared from Co/Pt multilayer by using laser interference lithography (LIL) while the Hall crosses for measuring a few dots are prepared in combination with focussed ion beam (FIB). The hysteresis loops from a few dots are showing significant Hall voltage jumps corresponding to magnetic response due to an inhomogeneous reversal mechanism because the intensity of the jumps is smaller than the expected value from a total magnetization reversal of one dot.

Research paper thumbnail of Anomalous Hall-effect measurement study on Co∕Pt nanosized dot

Journal of Applied Physics, 2005

Dot arrays made of polycrystalline Co/ Pt multilayer with an average grain size of 20 nm are fabr... more Dot arrays made of polycrystalline Co/ Pt multilayer with an average grain size of 20 nm are fabricated by using a laser interference lithography and their magnetic properties are examined by detecting anomalous Hall effect. It is revealed that the ratio of dots which have stable single domain state increases from 35% to 85% while the dot diameter decreased from 200 to 120 nm. The energy barrier height of magnetization reversal is estimated as 4.0ϫ 10 −12 erg from sweep rate dependence of the coercivity. The energy corresponds to the switching volume comparable with the volume of a physical grain in the multilayer film.

Research paper thumbnail of Magnetization process of high anisotropy CoPt nanosized dots

IEEE Transactions on Magnetics, 2005

Dot arrays with diameter ranging from 80 to 245 nm are made of Co 80 Pt 20 films with large perpe... more Dot arrays with diameter ranging from 80 to 245 nm are made of Co 80 Pt 20 films with large perpendicular anisotropy. Magnetic properties are investigated by detecting the anomalous Hall effect. The all arrays show angular dependence of remanent coercivity similar to coherent rotation. The result shows that reversal process is independent of dot diameter. The energy barrier height of magnetization reversal is estimated as 1.0 10 10 erg for the array consists of 140-nm-diameter dots. From the energy value, the switching volume is estimated as equivalent to the volume of a physical grain in the film. The results indicate that the reversal process starts from a nucleation of a "reversed grain" followed by propagation process.

Research paper thumbnail of Thermal stability and switching field distribution of CoNi/Pt patterned media

Microsystem Technologies, 2006

The thermal dependence and distribution of the switching fields of arrays of magnetic Co50Ni50/Pt... more The thermal dependence and distribution of the switching fields of arrays of magnetic Co50Ni50/Pt nanodots has been studied. These dots, with a diameter of 90 nm, are arranged in a hexagonal pattern with a periodicity of 300 nm. Field-dependent magnetic force microscopy was used to measure the switching field distribution of the array, which was found to range from 80 to 192 kA/m,

Research paper thumbnail of Probe Recording in Magnetic Patterned Media

In this paper we explain why future probe storage systems will use patterned media. As a model sy... more In this paper we explain why future probe storage systems will use patterned media. As a model system, magnetic patterned media will be discussed, even though their data density is limited to about . The first results on magnetic probe storage on patterned media are presented, and the problem of switching field distribution is discussed in detail. Finally we will present the first steps into two-dimensional coding for patterned media.