Synthesis and magnetic characterization of cobalt-substituted ferrite (CoxFe3−xO4) nanoparticles

This letter describes how composite material, made of maghemite (γ‐Fe2O3) nanoparticles embedded in a silica∕titania matrix, can be used to develop new magneto-optical planar waveguides. Thin film samples are coated on Pyrex™ substrates from a magnetic particles doped sol-gel preparation. M-lines spectroscopy measurements performed on these samples show that an out of plane magnetic field applied during the gelation induces a decrease of the planar waveguide phase mismatch. Free space measurements evidence the Faraday rotation of the films up to 25°∕cm at 633 nm. Improvements and leads of further works are proposed in term of magneto-optical waveguide applications.

Magneto-optical nanoparticle-doped silica-titania planar waveguides

Versatile transmission ellipsometry to study linear ferrofluid magneto-optics

It is shown that a simple photometric method provides high accurate result for the wavelength at which the retardance of a phase plate assumes the value π/2 . Result for a quartz quarterwave plate is presented and is found to be in high agreement with the result obtained by the modified Senarmont arrangement for simultaneous retardance measurement of two phase plates.

Evaluation of a photometric method for retardance measurement of a quarterwave phase plate

Both pure Fe3O4 magnetic fluids and containing polystyrene sphere composite magnetic fluids have been prepared. The magneto-optical characteristics such as magnetic birefringence and linear dichroism of both magnetic fluids and composite magnetic fluids have been investigated by the magneto-optically modulated double-frequency method. The results reveal that the order structure of nonmagnetic spheres and the interactions between the spheres and the neighbor magnetic chains of Fe3O4 particles in the composite magnetic fluids strongly affect the magneto-optical properties. The magneto-optical properties from the study can be used for further development of related new optical devices.

EFFECTS OF NONMAGNETIC SPHERES ON THE MAGNETO-OPTICS OF Fe3O4 COMPOSITE MAGNETIC FLUIDS

This paper describes a new high-precision automatized device to measure simultaneously optical parameters of retarder plates, and linear dichroism and birefringence on any material exibing those effects (natural or induced). As a test, measurements were made on a quarter wave plate, and a study on the dependency of dichroism and birefringence versus magnetic field on a ferrofluid was undertaken.

https://iopscience.iop.org/article/10.1088/0957-0233/7/2/006/pdf

P Daveze

Papers

A new automatized device for high-precision measurements of optical retarder plates