An “SD” card is sometimes used as a generic term to describe a memory card. When originally developed, they were quite small (by today’s standards). Over the years, techology and manufacturing has advanced to allow larger memory storage on these cards.
In essence:
SD > up to 2GB
SDHC > 4 - 32GB
SDXC > over 32 GB
Both the SDHC (High Capacity) and SDXC (X-Treme Capacity) are different formats than the old SD format. Newer devices that use these cards are usually backward-compatible, but not (usually) forward-compatible since they were manufactured before the newer card technology was developed.
Bottom line for your situation is to check your phone’s specs to see waht SD format it supports. A quick Google search on your phone model revealed the 1st hit as the manufacturer’s web page on this phone. If you click on the Specs link, you’ll find all the technical specifications including those for the Memory.
It says:
Total storage: 4GB/8GB, available capacity varies
RAM: 1GB
Expansion card slot supports microSD™ memory card for up to 128GB additional storage (card not included)
Note the last line. Your phone does indeed support (ie. can read and use) any card up to 128GB which includes SDXC. So you can use any micro-sized memory card your little heart desires (and your budget or wallet can afford). 
Hope this clears things up and helps.
