Chemical ordering in ilmenite-hematite bulk ceramics through proton irradiation

Abstract

We demonstrated the capability of MeV proton irradiation to promote chemical ordering processes in a solid at low temperature. We used the ilmenite–hematite solid solution system which allows estimation of the degree of ordering through measurement of its magnetization. Normally, ordering through diffusion would require high temperature annealing. At high temperatures, however, the equilibrium state would be less ordered and thus the achievable ordering incomplete. High energetic protons continuously transfer energy to the sample through electronic interaction which locally deposits large quantities of energy without a general increase of the sample temperature. This promotes diffusion processes which allow the system to relax towards the ordered equilibrium state.

Novel magnetic-semiconductors in modified iron titanates for radhard electronics

“…The results have been published in [13][14][15]. These papers discuss in greater depth the various mechanisms through which radiation can interact with materials and change their basic properties.…”

“…This experiment was done at the Cyclotron Institute of Texas A&M University using the proton source of the following parameters: 10 and 40 MeV, total fluence=5× 10 10 p/cm 2 , and exposure time ranging from 10 min to 4 h. From these results we conclude that resistivity remains unchanged from proton irradiation. However, the chemical ordering takes place resulting in increase of magnetic moments for a whole range of IHC [14].…”

“…Of special interests are IHF33 and IHC45, and single crystals of pseudobrookite (PsB). Some of these studies have been reported in references [6,7,[12][13][14][15][16][17][18][19]. In this paper our emphasis will be on materials characterization for radhard electronics, evaluation of magnetically and electrically tuned varistors and effect of a biasing voltage on the non-linear current-voltage (I-V) characteristics.…”

Growth and Characterization of Pulsed-Laser-Deposited Ilmenite–Hematite Thin Films

“…Radiation studies have shown that the magnetic properties are enhanced after irradiating these materials with protons while these properties remain unchanged after neutron irradiation. 9 They also have voltage-dependent resistivity, which makes them ideal materials for fabrication of varistors with low switching voltages and with applications in a radiation environment, for example space, nuclear reactors, etc. 10,11 Previously, thin films of IH using PLD were grown in vacuum and on sapphire substrates.…”

Magnetically tuned varistor-transistor hybrid device

“…6 Both IHC33 and IHC45 are also excellent radhard materials. 6,[8][9][10][11] Therefore, the devices described here are expected to perform satisfactorily even when exposed to radiations such as in space. The non-linear I-V characteristics for a wide range of compositions for ceramic samples of IH with 0 < x < 0.45 is reported in reference .…”