Broadband Dielectric Spectroscopy of Ruddlesden-Popper Sr$_{n+1}$Ti$_{n}$O$_{3n+1}$ ($n$ = 1, 2, 3) Thin Films

TL;DR

This study investigates the frequency-dependent dielectric properties of Ruddlesden-Popper Sr(n+1)Ti(n)O(3n+1) thin films across various temperatures and electric fields, revealing permittivity values and tunability characteristics.

Contribution

It provides detailed broadband dielectric measurements of Sr(n+1)Ti(n)O(3n+1) thin films up to 40 GHz, highlighting their permittivity and tunability behavior.

Findings

Permittivity increases at low temperatures.

Permittivity values are independent of frequency at room temperature.

Electric field tunability observed in Sr4Ti3O10 at low temperatures.

Abstract

We explore the frequency-dependent relative permittivity of Ruddlesden-Popper series Sr(n+1)Ti(n)O(3n+1) (n =1,2,3) thin films as a function of temperature and dc electric field. Interdigitated capacitors and coplanar waveguides were used to extract the frequency response from 500 Hz to 40 GHz. At room temperature, the in-plane relative permittivities obtained for Sr(n+1)Ti(n)O(3n+1) (n =1,2,3) were 42+/-3, 54+/-3, and 77+/-2, respectively, and were independent of frequency. At low temperatures, permittivity increases and electric field tunability develops in Sr(4)Ti(3)O(10).