Lithuanian Journal of Physics article / Lietuvos fizikos žurnalo straipsnis

INVESTIGATION OF DIELECTRIC AND MAGNETIC PROPERTIES OF AL-800 FERRITE
Saulius Rudys^a,b, Sergejus Balčiūnas^a, Christine Vollinger^c, Jūras Banys,^a and Vidmantas Kalendra^a
^aFaculty of Physics, Vilnius University, Saulėtekio 9, 10222 Vilnius, Lithuania
^bAntanas Gustaitis’ Aviation Insitute, Vilnius Gediminas Technical University, Linkmenų 28, 08217 Vilnius, Lithuania
^cCERN, Geneva, Switzerland
Email: vidmantas.kalendra@ff.vu.lt

Received 14 October 2022; accepted 18 October 2022

Ferrites are usually used in accelerators for tuning radiofrequency (RF) cavities and in nonreciprocal devices controlling the power flow in RF accelerating systems. The conventional parallel‐biased Ni Zn ferrites employed for varying the frequency of accelerating cavities have the disadvantage of high saturation magnetization (4πMs). Application of the transversely biased yttrium iron garnet (YIG) material in RF tuners promises a significant reduction of power loss compared with systems that use the longitudinal bias. To inject the beam and extract the beam out of the CERN accelerator rings the fast kicker magnets made from ferrite materials must be used. Power deposition in the kicker magnets can be a limitation: if the temperature of the ferrite yoke exceeds the Curie temperature, the beam will not be properly deflected. Investigation of the ferrite electromagnetic properties of materials up to the GHz frequency range is essential for a correct impedance evaluation. This report summarizes an approach for deriving electromagnetic properties as a function of both frequency and temperature of the AL-800 garnet material. This information will be useful for simulating ferrite behaviour under realistic operating conditions.
Keywords: ferrite, dielectric spectroscopy, magnetic permeability

AL-800 FERITO DIELEKTRINIŲ IR MAGNETINIŲ SAVYBIŲ TYRIMAI
Saulius Rudys^a,b, Sergejus Balčiūnas^a, Christine Vollinger^c, Jūras Banys,^a Vidmantas Kalendra^a

^aVilniaus universiteto Fizikos fakultetas, Vilnius, Lietuva
^bVilniaus Gedimino technikos universiteto Antano Gustaičio aviacijos institutas, Vilnius, Lietuva
^cCERN, Ženeva, Šveicarija

Feritai dažniausiai naudojami greitintuvuose radijo dažnių (RD) rezonatorių derinimui ir įrenginiuose, valdančiuose galios srautą RD greitinimo sistemose. Įprasti NiZn feritai, naudojami greitinančių rezonatorių dažniui keisti, turi didelį soties įmagnetėjimą (4πMs). Naudojant itrio geležies granato (IGG) medžiagas RD prietaisuose, galima žymiai sumažinti galios nuostolius, palyginti su sistemomis, naudojančiomis NiZn feritus. Viena iš alternatyvų yra naudoti komerciškai prieinamą IGG feritą AL-800 iš „National Magnetics Group“, tačiau gamintojas duomenų lape pateikia tik kelis parametrus, kurių nepakanka ferito veiklos modeliavimams, siekiant išanalizuoti tikras veiklos sąlygas. Šiame darbe buvo atlikti AL-800 ferito dielektrinių ir magnetinių savybių tyrimai plačiame dažnių ir temperatūrų intervale. Įvertintos dielektrinio laidumo vertės kambario temperatūroje yra maždaug 15,3 ir sumažėja iki 14,5, esant 5 K. Magnetinės skvarbos nuo dažnio priklausomybė yra tipinė feritams ir atsiranda dėl dviejų procesų, priskiriamų sukiniams ir domeno sienelių įtakai.

References / Nuorodos

[1] M.J. Barnes, L. Ducimetiére, T. Fowler, V. Senaj, and L. Sermeus, Injection and extraction magnets: kicker magnets, https://arxiv.org/abs/1103.1583v1 (2011),
https://doi.org/10.48550/arXiv.1103.1583
[2] L. Vega, A. Abanades, M.J. Barnes, V. Vlachodimitropoulos, and W. Weterings, Thermal analysis of the LHC injection kicker magnets, J. Phys. Conf. Ser. 874, 12017 (2017),
https://doi.org/10.1088/1742-6596/874/1/012100
[3] G. Rumolo, Beam instabilities, https://arxiv.org/abs/1601.05201v1 (2016),
https://doi.org/10.48550/arXiv.1601.05201
[4] M.J. Barnes, A. Adraktas, G. Bregliozzi, B. Goddard, L. Ducimetière, B. Salvant, J. Sestak, L. Vega Cid, W. Weterings, and C. Yin Vallgrenet, Operational experience of the upgraded LHC injection kicker magnets during Run 2 and future plans, J. Phys. Conf. Ser. 874, 012101 (2017),
https://doi.org/10.1088/1742-6596/874/1/012101
[5] V. Vlachodimitropoulos, M.J. Barnes, L. Ducimetière, L. Vega Cid, and W. Weterings, Study of an improved beam screen design for the LHC injection kicker magnet for HL-LHC, in: Proceedings of International Particle Accelerator Conference (JACoW, Geneva, Switzerland, 2017) pp. 3471–3474,
https://doi.org/10.18429/JACoW-IPAC2017-WEPVA094
[6] National Magnetics Group,
https://www.magneticsgroup.com
[7] J. Banys, S. Lapinskas, S. Rudys, S. Greicius, and R. Grigalaitis, High frequency measurements of ferroelectrics and related materials in coaxial line, Ferroelectrics 414(1), 64–69 (2011),
https://doi.org/10.1080/00150193.2011.577308
[8] J.M.D. Coey, Magnetism and Magnetic Materials (Cambridge University Press, New York, 2009),
https://doi.org/10.1017/CBO9780511845000
[9] R.M. White, Quantum Theory of Magnetism: Magnetic Properties of Materials (Springer, Berlin, 2007),
https://doi.org/10.1007/978-3-540-69025-2
[10] F. Kremer and A. Schönhals, Broadband Dielectric Spectroscopy (Springer, Heidelberg, 2003),
https://doi.org/10.1007/978-3-642-56120-7
[11] S. Rudys, M. Ivanov, and J. Banys, Ansoft HFSS software application for the dielectric and magnetic measurements of ferroelectrics and related materials in microwaves, Ferroelectrics 430(1), 115–122 (2012),
https://doi.org/10.1080/00150193.2012.677732