Artorix de la Cruz - Academia.edu (original) (raw)

Papers by Artorix de la Cruz

Research paper thumbnail of Determining the permeability of magnetic thin film material by magnetic force microscopy: relation with superconducting thin films

Physica B-condensed Matter, 2004

A generalized model to recover the magnetic permeability μ of linear magnetic medium thin films f... more A generalized model to recover the magnetic permeability μ of linear magnetic medium thin films from magnetic force microscopy (MFM), data under magnetostatic conditions is developed. In the mathematical treatment, where no assumption is made about the symmetry of the stray field, shape or magnetization for the MFM tip, we are lead to an inverse problem by entailing a nonlinear system of equations and obtain from the experimental data both physical magnitudes wanted: the thickness of the film bμ and μ. On the other hand, relations between superconducting and magnetic thin films are obtained, solving the problem of calibration functions and allowing to recover for a superconducting material the London penetration depth λ as well as the film thickness bλ.

Research paper thumbnail of CP-odd phase effects in a left-right symmetric chargino sector

Physical Review D, 2005

The left-right supersymmetric model contains a right-handed gaugino, as well as several higgsinos... more The left-right supersymmetric model contains a right-handed gaugino, as well as several higgsinos, in addition to the minimal supersymmetric model. Thus several CP-noninvariant phases appear in this sector. We analyze their impact on chargino masses and find that only two combinations are physically relevant. We then study the production of charginos in e+e- annihilation and chargino decays into a sneutrino and a lepton, and investigate the effects of CP-phases. We also study the CP-odd asymmetry in the production and subsequent decay at the linear collider with longitudinally polarized beams and find a large enhancement when the decay channel to the right sneutrino is available. The effects of the phases in the left-right supersymmetric chargino sector are different from the minimal supersymmetric standard model, and signals from this sector would be able to distinguish between different gauge symmetries.

Research paper thumbnail of Study of the Magnetic Film Materials by Horizontal Scanning Mode for the Magnetic Force Microscopy in Magnetostatic and ac Regimes

The magnetic force microscopy inverse problem for the case of horizontal scanning of a tip on a l... more The magnetic force microscopy inverse problem for the case of horizontal scanning of a tip on a linear magnetic film is introduced. We show the possibility to recover the magnetic permeability of the material from the experimental data by using the Hankel (Fourier-Bessel) transform inverse method (HIM). This method is applied to the case of a layered slab film as well. The inverse problem related to the ac MFM is introduced.

Research paper thumbnail of Analytical model for the levitation force between a small magnet and a superconducting cylinder in the critical state

Physica B-condensed Matter, 2002

In this work a simple analytical model is presented, which allows to obtain closed-form expressio... more In this work a simple analytical model is presented, which allows to obtain closed-form expressions for the maximum magnetic field trapped by a cylindrical superconductor as well as the levitation force between the sample and a small magnet. Previous models of this kind could not properly account for the behaviour of the repulsion force with the variation of the sample dimensions. In particular, the so-called Js+Jv model (J. Appl. Phys. 72 (1992) 1013) incorporates size effects by means of a surface current density (Js) which tends to zero for disc-shaped samples. However, we show that the features encountered both in experimental works and numerical models reported in the literature can be reproduced by a suitable modification of the Js+Jv model. Analytical expressions of the levitation force are obtained as a function of length and radius of the sample and as well the superconductor–magnet distance.

Research paper thumbnail of Analytical model for the levitation force between a small magnet and a superconducting cylinder in the critical state

Physica B-condensed Matter, 2002

In this work a simple analytical model is presented, which allows to obtain closed-form expressio... more In this work a simple analytical model is presented, which allows to obtain closed-form expressions for the maximum magnetic field trapped by a cylindrical superconductor as well as the levitation force between the sample and a small magnet. Previous models of this kind could not properly account for the behaviour of the repulsion force with the variation of the sample dimensions. In particular, the so-called Js+Jv model (J. Appl. Phys. 72 (1992) 1013) incorporates size effects by means of a surface current density (Js) which tends to zero for disc-shaped samples. However, we show that the features encountered both in experimental works and numerical models reported in the literature can be reproduced by a suitable modification of the Js+Jv model. Analytical expressions of the levitation force are obtained as a function of length and radius of the sample and as well the superconductor-magnet distance.

Research paper thumbnail of Determining the permeability of magnetic thin film material by magnetic force microscopy: relation with superconducting thin films

Physica B-condensed Matter, 2004

A generalized model to recover the magnetic permeability μ of linear magnetic medium thin films f... more A generalized model to recover the magnetic permeability μ of linear magnetic medium thin films from magnetic force microscopy (MFM), data under magnetostatic conditions is developed. In the mathematical treatment, where no assumption is made about the symmetry of the stray field, shape or magnetization for the MFM tip, we are lead to an inverse problem by entailing a nonlinear system of equations and obtain from the experimental data both physical magnitudes wanted: the thickness of the film bμ and μ. On the other hand, relations between superconducting and magnetic thin films are obtained, solving the problem of calibration functions and allowing to recover for a superconducting material the London penetration depth λ as well as the film thickness bλ.

Research paper thumbnail of CP-odd phase effects in a left-right symmetric chargino sector

Physical Review D, 2005

The left-right supersymmetric model contains a right-handed gaugino, as well as several higgsinos... more The left-right supersymmetric model contains a right-handed gaugino, as well as several higgsinos, in addition to the minimal supersymmetric model. Thus several CP-noninvariant phases appear in this sector. We analyze their impact on chargino masses and find that only two combinations are physically relevant. We then study the production of charginos in e+e- annihilation and chargino decays into a sneutrino and a lepton, and investigate the effects of CP-phases. We also study the CP-odd asymmetry in the production and subsequent decay at the linear collider with longitudinally polarized beams and find a large enhancement when the decay channel to the right sneutrino is available. The effects of the phases in the left-right supersymmetric chargino sector are different from the minimal supersymmetric standard model, and signals from this sector would be able to distinguish between different gauge symmetries.

Research paper thumbnail of Study of the Magnetic Film Materials by Horizontal Scanning Mode for the Magnetic Force Microscopy in Magnetostatic and ac Regimes

The magnetic force microscopy inverse problem for the case of horizontal scanning of a tip on a l... more The magnetic force microscopy inverse problem for the case of horizontal scanning of a tip on a linear magnetic film is introduced. We show the possibility to recover the magnetic permeability of the material from the experimental data by using the Hankel (Fourier-Bessel) transform inverse method (HIM). This method is applied to the case of a layered slab film as well. The inverse problem related to the ac MFM is introduced.

Research paper thumbnail of Analytical model for the levitation force between a small magnet and a superconducting cylinder in the critical state

Physica B-condensed Matter, 2002

In this work a simple analytical model is presented, which allows to obtain closed-form expressio... more In this work a simple analytical model is presented, which allows to obtain closed-form expressions for the maximum magnetic field trapped by a cylindrical superconductor as well as the levitation force between the sample and a small magnet. Previous models of this kind could not properly account for the behaviour of the repulsion force with the variation of the sample dimensions. In particular, the so-called Js+Jv model (J. Appl. Phys. 72 (1992) 1013) incorporates size effects by means of a surface current density (Js) which tends to zero for disc-shaped samples. However, we show that the features encountered both in experimental works and numerical models reported in the literature can be reproduced by a suitable modification of the Js+Jv model. Analytical expressions of the levitation force are obtained as a function of length and radius of the sample and as well the superconductor–magnet distance.

Research paper thumbnail of Analytical model for the levitation force between a small magnet and a superconducting cylinder in the critical state

Physica B-condensed Matter, 2002

In this work a simple analytical model is presented, which allows to obtain closed-form expressio... more In this work a simple analytical model is presented, which allows to obtain closed-form expressions for the maximum magnetic field trapped by a cylindrical superconductor as well as the levitation force between the sample and a small magnet. Previous models of this kind could not properly account for the behaviour of the repulsion force with the variation of the sample dimensions. In particular, the so-called Js+Jv model (J. Appl. Phys. 72 (1992) 1013) incorporates size effects by means of a surface current density (Js) which tends to zero for disc-shaped samples. However, we show that the features encountered both in experimental works and numerical models reported in the literature can be reproduced by a suitable modification of the Js+Jv model. Analytical expressions of the levitation force are obtained as a function of length and radius of the sample and as well the superconductor-magnet distance.