Magnetic sensors based on piezoelectric thin films made of environmentally friendly materials

MS-ECOP

Project summary

The magnetoelectric effect (ME) depends on the temperature and is currently a very important topic due to the need to investigate the physical phenomena involved and based on them to develop magnetic devices capable of working in various environments.

All types of electronic devices are subject to the limitations imposed primarily by the constituent materials. In the case of magnetic sensors, various piezoelectric or magnetostrictive materials can be used to obtain a high and temperature stable ME effect. For all these materials it is imperative to know the temperature variation of the electrical or magnetic properties. In our proposal we chose to study and develop a magnetic sensor based on environmentally friendly materials: calcium and zirconium doped barium titanate (BCZT) and magnetostrictive materials (Terfenol-D). A parametric study on temperature dependence for BCZT and Terfenol-D structures will be carried out and based on these results the best configuration will be chosen for the development of a magnetic sensor capable of working in the temperature range between -190C and 300C.

REZUMAT

Objective

The objective of this project is to develop a new magnetoelectric system, based on lead-free piezoelectric materials and magnetostrictive materials and to highlight the temperature dependence of ME coefficients.

Estimated results

Development of a new magnetic sensor architecture based on piezoelectric / magnetostrictive materials; evaluation of the sensors' response to temperature variation.

Implementation team

Dr. Ion Valentin CSII - project director
Dr. Nicu Doinel Scarisoreanu, CSI, key person
Dr. Filipescu Mihaela, CSI, Experienced research member
Dr. Viespe Cristian, CSI, Experienced research member
Dr. Zamfir Mihai Robert, CSIII, Experienced research member
Dr. Andrei Andreea, CSIII, Postdoctoral research member
PhD student Enea Nicoleta, ACS, PhD student member
PhD student Manica Dumitru, ACS, PhD student member
Ghitiu Ioan Mihail, Technological Development Engineer
Barbu Cristian Dan, Technician step III

Project stages

Stage I (04.01.2021-31.12.2021)

Stage Name:

Design of deposition experiments; parametric study on BCZT and terphenol-D thin films; highlighting the temperature dependence of material properties.

Stage Results:

2 ISI Articles

Activities:

Activity 1.1 Preparation of targets and target supports; adapting the experimental setup and purchasing materials.

Activity 1.2 Deposition and properties characterization of BCZT thin films

Activity 1.3 Deposition and properties characterization of Terfenol-D thin films

Stage summary

During this stage, conceptual and experimental models were developed for the realization of (Ba1-xCax) (ZryTi1-y) O3 (BCTZ) and Tb (1-x) Dy (x) Fe2 with x = 0.7 (Terphenol-D) thin films, followed by their deposition and characterization.

For the realization of the magnetic sensors based on the combined magnetostrictive-piezoelectric effect, the specific conditions for obtaining BCTZ (BaCaZrTiO3) thin films were determined. Pulsed laser ablation thin film (PLD) growth experiments were performed to obtain thin films based on Nb: SrTiO3 substrates, with variable thicknesses and clean surfaces with low roughness. The set of optimal parameters for obtaining piezoelectric layers of BCTZ was established. The effect of the electric field on the properties of BCTZ layers was studied and the phase transitions for 3 different BCTZx compositions were highlighted (x = 45, 50, 55).

Experiments were also performed for the deposition of Terphenol-D thin films of by PLD on Pt / Si, SrTiO3, DyScO3 substrates and their properties were characterized (topography, morphology, EDX, XRD, temperature dependent electric measurements).

The experimental results obtained during the stage were the subject of two oral presentations (one of which was awarded) at international conferences and two ISI articles under evaluation.

Figure 1: Experimental device used in activities 1.2 and 2.1

The experimental device used to obtain thin films by PLD is presented in figure 1 and consists of: 1. Laser; 2. Attenuator; 3. Mirror; 4. Focusing lens; 5. Quarter window; 6. Cap; 7. Reaction Chamber; 8. Vacuum hose; 9. High vacuum turbo pump; 10. Mechanical pump, for preliminary vacuum; 11. Digital interface for controlling Target Translation and Rotation; 12. Digital interface for oven control; 13. Oven; 14. Oven mounting bracket; 15. Rotation System Support; 16. Targets; 17. Translation System; 18. Rotation System; 19. Substrate; 20. Reaction Chamber windows.

Etapa II: (01.01.2022-31.12.2022): Adaptarea proprietatilor structurale și magnetoelectrice ale filmelor subtiri BCZT-Terfenol-D pentru aplicații ME; studiul dependentei de temperatura a efectului ME.

Rezumatul etapei

In cadrul acestei etape au fost continuate experimentele de obtinere a straturilor subtiri de Terfenol-D si BCTZ prin ablatie laser. Pentru realizarea senzorilor magnetici bazati pe efectul combinat magnetostrictiv-piezoelectric au fost determinate conditiile specifice pentru obtinerea de structuri lamelare de BCZT-Terfenol-D. Au fost realizate heterostructuri de BCTZ/Terfenol-D pe substraturi de Pt/Si si Nb:SrTiO3 stabilind setul de parametri din timpul procesului de ablatie, pentru obtinerea de heterostructuri functionale. Probele de Terfenol/BCTZ si BCTZ/terfenol au fost analizate prin diverse tehnici de investigatie: microscopie de format atomica (AFM), SEM, elipsometrie si tribonanoindentare. Au fost astfel pus in evidenta influenta parametrilor de depunere asupra proprietatilor heterostructurilor obtinute. Setul de parametrii din timpul depunerii a fost optimizat, astfel incat sa permita obtinerea de heterostructuri Terfenol/BCTZ cu proprietati adecvate si raspuns la camp magnetic.

Imagini SEM, in plan si in sectiune, pentru probe de BCTZ/Terfenol 0.6 si 0.7 depuse la temperatura de 400C

Imagini HR-TEM pentru proba de BCTZ depusa pe substrat de SrTiO3 si distributia de elemente chimice in functie de grosime.

Spectrele XRD pentru filmele de TD 0.6 si TD 0.7 depuse prin PLD la lungimea de undă de 266 nm.

Etapa III: (01.01.2023-31.12.2023): Dezvoltarea si obtinerea unui sensor magnetic bazat pe proprietatile magnetoelectrice ale structurilor BCZT-Terfenol-D

Variatia rezistentei electrice masurate pentru BCTZ/Terfenol depus prin PLD cu laser Nd:YAG (266 nm) cu plasma de descarcare RF 150W pentru: BCTZ/Terfenol 0.6/PtSi depus la 4000C si BCTZ/terfenol 0.7/PtSi

Pentru senzorii de BCTZ/Terfenol/PtSi (cu mentiunea ca intre BCTZ si terfenol exista un strat de titan cu rol de incapsulare si protectie contra oxidarii) masuratorile de rezistivitate difera foarte mult intre probele cu concentratii diferite de Tb/Dy. Pentru terfenol 0.6 se obtine o variatie a rezistentei cu temperatura aproximativ liniara, nefiind caracteristica nici metalelor nici oxizilor. Aceasta variatie liniara fiind un raspuns combinat al materialelor componente ale structurii analizate. Se evidentiaza 2 variatii bruste ale rezistentei masurate, una la temperatura de 215 Kelvin, caracteristica stratului de terfenol0.6 si a doua la temperatura de 335 K (620C) caracteristica stratului de BCTZ50. De mentionat faptul ca BCTZ50 prezinta o tranzitie din faza romboedrala in faza tetragonala la o temperatura de 37-400C nu la 62C

ETAPE

DISSEMINATION

The experimental results obtained in activity 2.1 are being published:

EMRS Conference - Fall Meeting (Online) - 20.09.2021 - 23.09.2021, Symposium R, Oral Presentation R.O6.7: "The role of chemical doping in Perovskites Thin Films" N. Enea, F. Andrei, ND Scarisoreanu, V. Ion

ICPAM Conference 13 - 23.09.2021- 30.09.2021 Sant Feliu de Guixols, Spain, Oral presentation: N. Enea, V. Ion, ND Scarisoreanu, F. Andrei, - "The role of strain engineering on ferroelectric perovskites thin films obtained by laser techniques "Award: The best oral presentation delivered by a young scientist -Nicoleta Enea

Articles submitted for publication:

1. Lead-free (Ba,Ca)(Ti,Zr)O3 thin films with tailored Pockels-Kerr effects for silicon photonics
Autors: N. D. Scarisoreanu, F. Craciun, V. Teodorescu, I. Alexandrou, C. Mitterbauer, V. Ion, N. Enea and M. Dinescu

Pockels and Kerr effects are linear and non-linear electro-optical effects respectively used in many applications. For example, the modulation of the refractive index is employed in optical modulators used in photonic circuits. But the greatest challenge is in photonic elements for quantum computing at room temperature. For this aim materials with strong Pockels/Kerr effects and (2)/(3) nonlinear susceptibilities are necessary. Here we demonstrate compositional-modulated strong electro-optical response in epitaxial films of (Ba,Ca)(Ti,Zr)O3 lead-free perovskite titanate. These films are grown by pulsed laser deposition (PLD) on SrTiO3, making the heterostructure easily integrable on silicon and thus compatible with silicon technology, especially due to PLD possibility to grow films on large wafer surfaces. Depending on the ratio Ca/Ba and Ti/Zr, films show high Pockels or Kerr optical nonlinearities. We relate the variable electro-optic response to the occurrence of nanopolar domains with different symmetries in a selected composition range. These findings open the route to easily implement nonlinear optical elements in integrated photonic circuits.
Acknowledgements: This work was supported by a grant of the Ministry of Research, Innovation and Digitization, CNCS- UEFISCDI, project number PN-III-P4-ID-PCE-2020-2921, within PNCDI III

3. Thin film of oxidized Terfenol-D obtained by Pulsed Laser Ablation
Autors: I. Ghitiu, N. Enea, V. Ion, A. Andrei and N.D.Scarisoreanu
1National Institute for Laser, Plasma and Radiation Physics, Magurele, Bucharest, Romania
corresponding: nicoleta.enea@inflpr.ro

Abstract:
Temperature sensitivity of the magnetoelectric effect, represents an important research topic due to the necessity of understanding the physical phenomena that occur with this effect and the need of developing suitable sensors dedicated to work in special environments. Piezoelectric-magnetostrictive laminated composite is a simple structure, “easy to fabricate”, it presents a high ME coefficient and can have applications in various fields, such as magnetic sensors, magnetoelectric transducers or in green energy harvesting. Terfenol-D presents one of the best magnetostriction coefficients, but its disadvantages stem from its dependence on magnetic properties of temperature.
Given the composition of this material, finding a suitable experimental route to grow good quality thin films is a challenge. In the present paper work, we report the parametric study and growth properties of Terfenol-D thin films using the Pulsed Laser Deposition (PLD) technique on different substrates, such as Pt/Si, SrTiO3, DyScO3.
The properties of Terfenol-D thin films have been studied with the help of several investigative techniques: Atomic force microscopy - AFM (topographic studies); Scanning electron microscopy - SEM (morphological studies), X-ray diffraction - XRD (crystal structure), spectroelipsometry (optical studies) and electrical / magnetic temperature measurements.
Acknowledgements: This work was supported by a grant of the Ministry of Research, Innovation and Digitization, CNCS - UEFISCDI, project number PN-III-P4-ID-PCE-2020-2921, within PNCDI III

DISEMINARE

CONTACT

Valentin Ion: valentin.ion@inflpr.ro
Photoplasmat Center: https://fotoplasmat.inflpr.ro/new/